Even if OP was lieing, what's so horrible about giving someone some attention? Either you can call him out and risk being wrong and looking like a jerk, or you can just have a grain of empathy and act like you believe him. It's not going to do any damage
Also could you guys just try and have a tiny bit of respect? Being suicidal doesn't make you a wimpy baby that can't deal with anything, and it doesn't make you a mental whack job. Some people just have extremely difficult situations that wear on them over time, there are just some things that few people can handle without help.