My mental health is patchy but, mate, I have a mate who’s all over the ship. He’s quite often delusional and I dunno how to help him. I mean, matey, I’m hardly doing all that bright.
I have a similar situation. To be honest, I too had no idea what to do other than to nudge them in the direction of services that can help. I felt pretty powerless and sad for my friend.
It may be that you have to focus on your own health journey before you can help your friend.