This is something I've always wondered myself. I just posted in intro but I lost my brother to suicide, he just turned 14 years old. I'm Roman Catholic and I've been taught that yes it's a mortal sin and Mark won't get into heaven. I was taught that we are stewards, not owners, of the life God has entrusted to us. It is not ours to dispose of. But I can't believe that God would do that.