if he says he went out and claimed to try and didnt have the energy to do it thats a good thing i think as it means hes not serious about it and its more a cry for help...
the problem is figuring out how you can help him... how you can satisfy him and solve any issues he has.
if your really concerned about it with everything you have said you can have him sectioned for his own safety to prevent any suicide attempt, that way he can be under monitor at all times in a safe secure location for a period of time, then he may get whatever help they can provide to do with it.
