You seem determined not to learn anything, and instead continue asserting your "rightness". I guess that's ok, but I feel compelled to correct you so that anyone else reading this thread is given the opportunity to try and understand what happened.
IF the judge had found that Mom was neglecting the child's health or education, the judge would have changed custody WITHOUT YOU REQUESTING IT. The judge did not, because the judge did not find that Mom was neglecting the child's welfare.
The judge MAY have found that Mom was not serving the child's best interests by home-schooling, but that's not the same thing as neglect. Neglect has a legal definition. In SC, that definition is:
Child abuse or neglect occurs when the parent, guardian, or other person responsible for the child’s welfare:
Inflicts or allows to be inflicted upon the child physical or mental injury or engages in acts or omissions which present a substantial risk of physical or mental injury to the child, including injuries sustained as a result of excessive corporal punishment, but excluding corporal punishment or physical discipline which:
Is administered by a parent or person in loco parentis
Is perpetrated for the sole purpose of restraining or correcting the child
Is reasonable in manner and moderate in degree
Has not brought about permanent or lasting damage to the child
Is not reckless or grossly negligent behavior by the parents
Commits or allows to be committed against the child a sexual offense as defined by the laws of this State or engages in acts or omissions that present a substantial risk that a sexual offense as defined in the laws of this State would be committed against the child.
Abandons the child
Encourages, condones, or approves the commission of delinquent acts by the child and the commission of the acts are shown to be the result of the encouragement, or approval
Fails to supply the child with:
Adequate food, clothing, shelter, or supervision appropriate to the child’s age and development
Education as required by law. A child’s absences from school may not be considered abuse or neglect unless the school has made efforts to bring about the child’s attendance, and those efforts were unsuccessful because of the parents’ refusal to cooperate.
Health care; though financially able to do so or offered financial or other reasonable means to do so and the failure to do so has caused or presents a substantial risk of causing physical or mental injury. For the purpose of this chapter "adequate health care" includes any medical or nonmedical remedial health care permitted or authorized under state law
Has committed abuse or neglect as described in in previous paragraphs, such that a child who subsequently becomes part of the person’s household is at substantial risk of one of those forms of abuse or neglect.
What you have repeatedly described does NOT reach that level. So you continuing to insist that you proved that Mom was neglecting the child AND YET, the judge STILL felt that the child's best interests were best served by remaining in Mom's household and Mom's "failing school" makes no sense.
SC does allow one parent to have final decision-making, in spite of a determination of joint custody. I still believe you'll find it impossible to work with considering the child is with Mom most of the time. And, you'll find that it doesn't apply to day to day decisions. Mom can still choose not to take the child to the doctor because he's vomiting. Mom can still choose to allow child to stay home from school if he's ill. Mom can still make all day to day decisions for the child while in her care. You will have final say ONLY on major decisions - surgery, braces, changing schools, etc. And, only until the child reaches medical majority, which in SC is 16 years old. After that? Junior can make all of his OWN medical decisions with the exception of those that are "essential to life". You (nor Mom) will have NO right to interfere with ANY routine medical decisions after that point. After the age of 17, the child will be making all of his own educational decisions.
It MATTERS that you understand these things. It MATTERS that you understand that as of right now, Mom has primary custody. You have secondary custody. Mom will retain primary custody until and unless a court decides otherwise. And a court can only even CONSIDER a change if a material change in circumstances since the LAST HEARING has taken place. That really does mean that nothing at all that happened the day before the hearing matters - ever again.
Consider this:
To convince the family court to CHANGE custody, a parent must prove three things:
1. A material change in circumstances;
2. The material change in circumstances happened AFTER the most recent family court custody order; and
3. The material change substantially affects the child’s best interests.
When Would the Family Court Modify a Custody Order in South Carolina?
Generally, to justify a change of custody, the family court looks to see whether there have been negative changes in the custodial parent’s skills or lifestyle. Here are a few examples of poor parenting or lifestyle choices that may cause the family court to change custody:
Interfering with the Relationship Between the Child and the Noncustodial Parent.
Unfortunately, some custodial parents try to drive a wedge between the child and the other parent. Examples of this include bad-mouthing the other parent in the child’s presence, obstructing visitation and communication between the parent and child, and making false allegations against the other parent to restrict their visitation. Most family court judges will give the custodial parent an opportunity to change their negative behaviors, but if their conduct continues, then the court may change custody.
Immoral Conduct. The family court will change custody if the custodial parent engages in immoral conduct that impacts the child’s welfare. Examples of immoral conduct include exposing the child to overnight romantic guests, exposing the child to pornography or other age-inappropriate materials or behaviors, drug use, and alcohol abuse.
Educational Problems.
If a child performs poorly at school, and the custodial parent is contributing to the problem or does little to help the child, then the court may change custody. Examples include excessive tardiness or absences from school or failing to get tutoring or other assistance for a child that is struggling with their courses.
Unstable Home Environment. Many things can negatively impact the stability of a child’s home environment based on the custodial parent’s choices. Examples include excessively moving from home to home, lack of job and income stability, and the custodial parent’s over-dependence on their family for support.
Poor Parenting Skills. Poor parenting skills come in many forms. Examples include behaviors that keep the child from developing independence, responsibility, or maturity, elevation by the custodial parent of their own happiness over that of their child, and improper or no supervision of the child, and mental or physical abuse of the child.
ANY of those things must be NEW. Not a continuation of issues you've had with Mom.
What you won, is that your child must be enrolled in a public school - either the one in Mom's district or the one in yours. And you were awarded joint custody with final (major) decision-making.
But no matter how many times you say it's true, you didn't prove Mom neglectful or unfit, and Mom didn't really "lose" anything.