I feel for You and your Family,and I know from experience the pain.
My Dad was mad at Mom,and the day before His 77th Birthday went out in the shop to end it while Mom was in town getting a cake.
The Sherriffs dept took the firearm used ,asked nothing about any others ,showed me a note to Identify Dad's hand writing and left after investigation and Dad was removed.Mom got said firearm about 30 days later,unloaded and ziptied thru triggerguard/cyl,which She later sold while visiting in another state [thru dealer];She wanted no family member to have it but did'nt have it destroyed.
Over the yrs,I was directed to destroy firearms,the worst to me was a Colt .38,and I happened to know where it came from.Most of the time they were junk.
Again, sorry for Your loss,It will stay with you,but time heals,just sometimes Slowly.