Hey Charlie!

I’ll just give you my very personal opinion. Seems like you’ve been caught up between your friends codependent behaviour and your own …
I think it is completely ok to tell him that it hurts you to see this and what you think about it – because you care, and that is what friends are for. You don’t have to pretend everything is fine and you can stand by what you think.
However, as obviously shitty as the situation sounds, as a friend you also have to respect his decisions. Don’t fall into the trap of controlling/manipulating his life, even if you only wish the best for him. You will only create a new codependency. He is a grown man, and he needs to learn healthy interdependance – getting your honest opinion, and making his own decisions and mistakes if needed.
At the same time you might want to look into why this triggers you so much, and how your friendship is constructed… do you take on a “healer” or “helper” position very often? Do you want to sustain the friendship by being needed by him? Can YOU draw healthy boundaries in terms of letting things go that you cannot change or that are not your responsibility? (Btw that does not mean you don’t care).

A lot of projections of my own stuff again here, so feel free to dismiss this if I’m off.