I’m so glad I saw this because I myself for a long time was in denial I had anything wrong prior to medication, and then it was like putting on glasses for the first time.
Not only is your son’s father putting him in more danger by keeping him on, then ff (when with him), his medication. This is complicated for many reasons but in short if he isn’t taking it daily, not necessarily including the weekends, it could make his symptoms worse instead of better.
I’m sure I’m telling Noah about the flood now, so please forgive me, but you’re husband’s tactics are damaging for you, for your son, for the relationship between both of you and your son, and even if the father’s actions are strictly out of concern, his ignorance for data and easily researchable questions via wifi/4g points toward lazy, or at worst manipulative or borderline narcissistic. If your son is only at Dad’s on the weekends, then maybe this is an option, but be aware that being on meds 24/7 can create resistance and more will be needed to obtain the same efficacy (this sometimes happens slowly so keep an eye, since he young up the dose as slowly as possible and only when needed). My psychiatrist said take time off on weekends but I’m now in medical school so take as needed (see, I turned out fine, mostly lol jk).
The worst outcome from this situation isn’t just related to your son’s ADHD medication and whether he is taking it or not, but that his father slowly seems to be undermining your authority, by going against what you as his mother knows is best. I know for a fact that because you were not only willing to put your son on adhd medication, but notice something wasn’t particularly working at school or elsewhere, and wanted to seek out on your own volition an answer to create an experience for him that is as fun and normal, not to mention nurturing,as possible,one in which he can grow up to thrive. His dad’s opposition to your actions not only are unwarranted but as he grows into teenage years he might eve be more at risk for thrill seeking behaviors (more so than teenagers in general, I mean).
Luckily both ADHD and intelligence are highly heritable, and being as you get your ability to be intelligent from your mother’s side in largely higher proportion, he sounds like a great kid who’s dad just needs to be force fed the science lol. It’s also a man thing to be against taking pills in general, but in this case especially it’s not advised as per brain chemistry reasons stated just above.
You sound like an amazing mum–the kind of support one needs when being diagnosed with ADHD is huge, and it really does make or break your goals and self-concept for the rest of your adult life (getting on top of that now is key).
Random thought that might work re:dad, if it is a power thing, maybe give him power over something else related to son like nights out at a movie or sports games together. He will think he has more power or that hes held in esteem which will only make him better in the future. Good luck!