Mental issue. Hellucinating thoughts.

My brother is 33. He has lost his job. It been 5 years. He is now living his life in phases. Phase 1 where by is perfectly normal. Phase 2 he is only engrosed with his thoughts. He talks to himself and looks like he trying to fix something back at job he use to work earlier. When he is in this phase he talks about unrealistic things.. Like some one controlling his brain, Planting thoughts in his head etc. His job loss was a difficult period in his life and I remember he has issues with management as well which he now recall as someone trying to harm him . This two phase are of 3/4 months. And one repeats after the other. Please let me know what can be done to make him live a normal life without these hellucinating thoughts.