I just don't know - that is a big question, but I disagree with you that taking your life is the most sincere form of remorse and repentance.
My mother took her own life, but she was severely mentally ill. I don't know how God judged her for that.
In most suicides, people are completely lucid and are not clinically insane.
I read a story once about a woman who took her own life, but was revived and survived. She had a "near death" experience of being in a terrible place, and her a voice saying that killing herself was the "worst thing she could have done." Murder itself is evil because it is an assault on God's image (us), and it is spitting the face of the Almighty who gives us life itself.
I truly believe that he was not in full consent of his will at the time of his death. Sounds the same with your mom.