I'm so sorry. My cousin-in-law's mother committed suicide last year after being diagnosed with ALS & I saw what it did to the family. Every one of them feel guilty, as if they could have prevented her from taking her own life, but it was not preventable. Their grief is so much different than mine, losing my Mom to cancer. It's bad enough when God calls a loved one home! I'm just so very sorry. I will keep you & your family in my thoughts & prayers.
Please don't take on any guilt.