I’m scared that my bf is going to kill himself

My bf has a habit of pulling away once every month or so and not communicate for a whole day. Just last week when we were talking he told me he understands why some people are suicidal, so I directly asked him if he has suicidal thoughts and he immediately brushed me off saying that he’s had them for years and for me to forget he’s ever said anything. Just today he went through another depressive episode. I tried texting him about it and asking what’s wrong and he said he doesn’t know what’s wrong and he doesn’t feel like talking. I was checking his location since I was a bit worried and I saw him at what appeared to be a firearms shop (he’s never expressed interest in that stuff before) I tried contacting him and asking if he’s safe, but he hasn’t responded I’m terrified that he’s gonna do it.