Mental illness

Need some advice on how to handle this situation. My uncle is having some serious issues with bipolar and depression. I feel terrible for what he’s going through but it’s gotten worse lately. It’s been many years that he’s been dealing with it but now he decided to take himself off of his lithium and just remain on his one med. since then he’s become angry, mean and honestly he’s scary to be around. He’s yelling at everyone he cursed me out, he doesn’t ever use that language , he’s been drinking, he never drank just wasn’t his thing and he was screaming and yelling and pushed my 17 yr old niece the other day while we were staying at his beach house. He told my mom they need a break from each other so he blocked her now she can’t reach him. The psychiatrist has tried to call but he doesn’t answer. Is there anything that we can do? Now he wants a divorce from his wife as well. He’s manic now so he goes up and down a lot . He cursed me out and then txt my husband that he wants to invest in his business. It’s very strange. Not sure what to do anymore