What do you do if a loved one is depressed but they won't do anything about it?

[Jemster]

I'm so worried about my brother. He's been depressed on & off for a few years now since his marriage broke down. Sometimes he's opened up to me but then he'll just not mention it again for months. I tried to get him to go to GP a while back for ad's but he wasn't keen as he said he'd tried before and didn't like the side effects. He lives on his own & I worry as he seems so lonely, although he does have children he sees.

On top of this my dad has dementia which is causing my mum a lot of stress & I have anxiety in particular health anxiety.
I feel so worried all the time about all these people I love but can't make better.