Can I avoid a mentally challenged coworker and kinda dislike him?
Have you ever talked to him? What did he say when you brought up his handicap?
He was sensitive about the subject and said that he is actually ok with his mental status. He felt offended when I mentioned it to him
You shouldn't avoid people for their disability. It makes you look shallow and other workers will avoid you in return.
I'm not like that
If you are not biased then you should not avoid your coworker or treat him differently in any way.