I am sorry for your loss.
It's a personal decision whether to take the children to the funeral or not. My children definitely attended the funerals of their grandparents - and they were very small when their granddad died. There are ways of explaining this to young children.
As for the counseling though, it is possible to get a judge to order it. I suspect dad is saying no because couselour are MANDATED reporters. Just a feeling.
If child protective services is recommending it - jump all over it. What is dad going to say to the judge? I don't care that they are recommending it. I said, "NO." Won't fly.