Even the mercs that would be "kinder" about it would probably still infantalize him, maybe not wanting to fuck him anymore as they feel they're taking advantage of him. Meanwhile he's a grown man in his 50's that built a magical healing gun that can make people invincible for a bit, and is arguably one of the top three smartest people on the team behind Engie (possibly Spy in second). Engie would be the type to infantalize him, maybe unintentionally, or intentionally if he's feeling sadistic. Spy definitely would intentionally, knowing full well it'd piss Medic off. Scout and Sniper would become full-on nasty to him. Scout bullies and roughs him up, squeezes an old baseball helmet onto him and shoves a mouthguard into Medic's mouth, framing it as a way to stay safe during battles/"so [he] doesn't slobber all over himself". Sniper sneers at him n calls him a retard, pointedly tells Medic it's no wonder he lost his medical license/doubts he even really had one in the first place. Which just further confuses Medic, outright telling Sniper that he's autistic, probably was even the one to diagnose him. Sniper scoffs and tells him it's very unprofessional to project onto his own patients. I don't think Soldier knows what autism is but he sees Scout forcing the helmet onto Medic and finds it amusing, calls him and Medic helmet buddies. Pyro gains a new obsession with Medic and won't lay off him, now more than ever. Demo just kinda brushes him off to the side, maybe considers him a "bottom of the barrel" fuck even more than before, beyond just the fact that he's fucking a slut. Heavy grabs him and goes even tougher than before, Medic initially enjoying it quite a lot but then it starts to hurt and Heavy doesn't listen to his pleas to slow down let alone stop, figures his doktor isn't "fucking stupid" as he heard of of the teammates say, he just wants to be "fucked stupid."

In all seriousness I don't think most of the team would actually care, Scout of course would have his jokes and Spy might be pleased to find exploitable weaknesses should they benefit himself. But in the case of Medic abuse, it's a whole new way to fuck him over and I'm honestly surprised I haven't considered it before.