For what its worth, no matter how much i didnt care about halacha, i would never (and still never do now) watch tv in my parents house on shabbos nor pull up in my car. I explain to my children now that we do not watch tv or play with muktza toys when we are there on shabbos. I am careful in my mother’s kitchen with kashrus (and when i go to sit with my father in shul, ironically talk than many of the ballah battim.)
There is a difference between being non-observant and being disrespectful (although you may feel like they are one and the same).
My point is, whether your son wants to be on or off the(your) derech, or somewhere in between (MO, bnei akiva, ncsy, conservadox, whatever) if he wants respect for his decision he should show respect for yours and your way of life.