Could my friend have Bipolar Disorder? He sees things and has weird mood swings!?

He says that he sees shadowy figures standing around that resemble real people. However, once he gets the chance to notice them, they disappear. It sounds very scary. He also has weird mood swings. One moment he is happy, then the nex he is angry or sad. Just today, he said that he almost fainted when he said that he was welcomed by a formidable shadow person when he opened a cubboard door, but it then faded away. He got freaked out and then ran down the staircase, just to find a shadowy hand reaching out of a nearby door, and then disappearing. I think that he is going crazy, and may have Bipolar Disorder. If he does have it, it would add another disorder to his list. He already has a serious case of obsessive-compulsive disorder. Can anybody help him?