Guilt is a form of self hatred. Self hatred is the only sin. As Petros said, hating god is self hatred too. We are all part of god. Everything is interconnected and interdependent.
Sometimes suicide is a form of revenge. "You hurt me, so live with the guilt of this!"
The best part of revenge is being able to see the look on the person's face, suicide prevents that. It is sure to mess up all future family get together, that is who it is intended to hurt and in most if not all cases they are the right party that should be affected because something in that 'support unit' broke.
Unfortunately when something is broken it is best to move back a certain distance, going closer takes a lot of work and a lot of time and a lot of real changes. That doesn't happen very often, a comfortable distance is the normal solution meaning it is never repaired. As long as your new family has the traits that were not a problem before and hopefully the other ones are missing or can get repaired as they crop up.
Suicide certainly has no bearing on what happens after death.
Ec:3:20:
All go unto one place;
all are of the dust,
and all turn to dust again.
Ec:12:7:
Then shall the dust return to the earth as it was:
and the spirit shall return unto God who gave it.
Ec:9:10:
Whatsoever thy hand findeth to do,
do it with thy might;
for there is no work,
nor device,
nor knowledge,
nor wisdom,
in the grave,
whither thou goest.
It doesn't matter which path you choose to get there, only that eventually you get there. I doubt very much that we can do all there is to do in one lifetime.
The more a body fails a person the less they want it to last forever. `most people who die of old age are quite comfortable with the coming change. A few grinders is a few teeth, a back bends in old age and the eyes become dim.
Ec:12:3:
In the day when the keepers of the house shall tremble,
and the strong men shall bow themselves,
and the grinders cease because they are few,
and those that look out of the windows be darkened,