Where exactly is he?

You can give your companions a total of 6 perks, but there's a 7th one they get once you complete their particular quests. In Max's case it's TUNED IN. If you don't like it you can even respec your character and give them 7 new perks.

Tuned In perk gives "Drug Effect Duration +50%"

But max didn’t go to my ship how do I get him to join my party

I told him I didn't want him to join my party originally, before I knew there were only 6 companions in the game. Now I can't get the prompt again. Did I miss my chance?

His quests ending makes no sense. He just changes from one extreme to another

should put party comments in the trivia section! for example, parvati and max in the part reveals that he has a bad knee. stuff like that

What? I didn't get any of these endings?

if you are going to make a wiki for a game, get the basic information right. Vicar Max joined the OSI, not the 051. In the paragraph directly about that glaring error, it is correctly identified as the Office of Scientific Inquiry; 12 words later and you couldn't remember?