My friend has many mental illnesses and and disorders and he's so proud of it. I'm concerned that this may lead to behaviours that may harm him.
He currently has depression, anxiety, bipolar disorder and ptsd diagnosed but he keeps looking for more things to add. This is not a joke.

His cousin recently got diagnosed with more disorders than him and he got very jealous.

He recently has been trying to convince himself and others that he has autism or that he is on the spectrum but I don't think he is correct (nothing wrong with being autistic at all!). He tries to make every little things about himself fit into being autistic and it's mostly very broad things that are stereotypically related to autism that most people can relate to on a certain level.

He also likes looking at niche disorders that most people have not even heard of and try to self diagnose.
I tell him to please speak to a professional before self diagnosing and claiming a disorder but he does not listen.

He also like to pin disorders on me and diagnose me with things and that makes me very uncomfortable.

What can I do in this situation? I am worried about my friend.