None of us really knows for sure, because we are all still living. So no answer is 100%. In my most humble opinion, I would say, a person would end up in a state of low vibration. Because if you are open to the idea of suicide, even if it's to end illness, physically or not, you are in such a state where you are so down from it, you are giving up so to speak. Well, that is a crass term to bluntly say "giving up" because I know it is more than that.
In that state where the turmoil is so deep, and so strong, it's going to leave a mark on you, even after you pass. Putting you in a low vibration. I would not be surprised if many that do, that end up up taking them selves, have a higher chance of becoming earth bound, and just wandering around for a time, until they regain themselves.
Life never goes the way we expect it to, but always takes us where we need to be.