For those outside NY, the background info you need to make sense out of this is that PBA cards, which come in different "denominations" (officer, sergeant, etc.), while ostensibly are to show your "membership" in the PBA, are in practice "get out of jail free" cards. As a professional courtesy,
some officers will, upon ascertaining the relationship between the card holder and the PBA member, will be more likely to cut them some slack. PBA cards from higher ranks confer proportionally more clout in this regard.
Frequently, they are accompanied by "courtesy badges" (I assume these exist in other states), which are miniature badges of an actual officer that are traditionally given to family members. A combo of a current PBA card and a courtesy badge almost ensures that for all minor (and some major) infractions, you'll be let off with a warning.
That being said, I have seen many times where an officer will take the PBA card/badge and contact the officer who handed it out to have him/her come collect it, frequently right at the traffic stop. Not funny when the person who gave it to you is your Detective father