Thoughts on Islamic Funeral Customs

Assalamu alaikum. I’ve got a question about Islamic beliefs, not trying to share a sad tale. Just to be clear, I’m not a Muslim myself. My dad, who was from Iran, passed away from suicide when I was 15. He was more of a cultural Muslim when I was around-sometimes he’d pray on a mat, but not super regularly. At his janazah, my wealthy Iranian uncles got into heated debates with the police, insisting it wasn’t suicide, and they really pushed me to see things their way, even though it didn’t match what I felt. It seemed like in their view, suicide is a huge, unforgivable wrong, and if I didn’t accept their side, I was being judgmental. After the burial, they looked at me, said I had to step up as the man of the family and handle the finances. Then they left, and I never heard from them again. Looking back, they drank alcohol, flaunted flashy jewelry, and seemed pretty self-centered. Maybe that’s more about their cultural background than faith? Anyway, my real question is: how does what I went through connect with the deeper Islamic teachings and traditions?