The response to "You should just get over it", is "No, YOU should just get over it. What is more reasonable? Someone with a problem trying to fix or mitigate the problem, or everyone else having to make adjustments for them, forever?" But said in a less blunt, more indirect way. It's hard getting around people's defences to make them see reason. Really, you have to "let" them see things by themself, rather than "imposing" things on them. I'm not great at it myself. It takes patience, a special kind of understanding of their personal worldview, and strategy. THAT'S what therapists are for.
I find it really easy to talk to people I don't know. I mean, what pressure is there if you never have to see them again if you don't want to?
There are different drugs. Experimenting is a part of the process. And drugs, in my opinion, are ideally a temporary thing - just a bootstrap measure to get you functioning well enough that other things (therapy, self-help, ..) can take over.
I'm not sure if you can reason him into going through with this stuff, but his objections in the face of logic might be insightful.
"I think he's just scared because things are changing for me and he's at a standstill in his own life and doesn't know how to get out of his rut.". Offer him your theory, and reassure him it's okay to feel like that, and there is help available, and even if one thing doesn't work, there are other things to try.