Scared for Friend

My best friend recently shared with me that he is struggling and finds himself in a dark and at times scary place. He didnt say depressed but everything he did say would suggest it. Also sounds like he has had some suicidal thoughts. I also recently learned he identifies as LGBTQ+ but he is not out and doesnt know I know. Although not 100% sure...do think he is hooking up with men through Grindr. Not his personality to be promiscuous. He is someone that cares greatly about people and making connections. Worry its the depression that is driving him and that it makes it worse and our last few interactions he seems so uncomfortable around me and like he feels shame. Not sure what to do.