First and foremost, I’m truly sorry for your loss. Words otherwise fail me here.
Second of all, when your minds starts processing this DO NOT blame yourself. I know you were having a rough time with him and knew he wasn’t doing well but you couldn’t predict this and would otherwise have been powerless to stop it. This isn’t anyones fault, nobody made him do it and nobody takes that step without some serious issues on top of them. Sadly, from the outside, unless they share that burden you might never know.
This is a different kind of grief and not something I’d wish on anyone. If you want to talk there are folk here who have dealt with suicide, who can help you process this and ultimately get through this. It’s rough but you will. But most of all take care of yourself and your family.
Again, my condolences.