Be open and honest about what you are seeing. Ask what you can do to help. Don't label. If the conversation goes well and your friend opens up, be ready to help

Be open and honest about what you are seeing. Ask what you can do to help. Don't label. If the conversation goes well and your friend opens up, be ready to help them find help. I would be careful of going in prepared with e.g. a psychiatrist's phone number, because you don't want to send signals, "hey, we think you are mentally ill". If the conversation goes poorly, back off and try again later. While it is good to not have every person in your social group having this conversation, having more than one person have it is probably a good idea. You don't want the friend to get the feeling "everybody is against me" while at the same time, if it's just you, they can more easily ignore your input as "just you". Finally, recognize that this might cost you a friend. But if you do care for that friend (which obviously you do), that is a risk worth taking for your friend's sake. Good luck.