help me help my friend?

my friend just started dating this girl.(that is hot)at first he thought she was on meth but he brought her to his house for the weekend and my wife and I ment her. we both thought she was on meth to.but after I thought about it for a while I figured out she had Schizophrenia(I had an uncle this way so I knew some of the symptoms)we have kinda thought she is not taking any medications.My friend really likes her and I think she likes him but he is scared about the hole deal.Has anyone ever delt with these people in a relashionship?How should he go about asking her to take her meds?He keeps asking me what I think he should do.I keep telling him to hold out and see what happens.I’m I wrong to tell him this?Should I tell him to run and never look back?