It has been a while since I used FTM and maybe you can't answer this, but I know that GEDCOM allows for a "Y" flag on the DEAT tag to indicate Dead but don't know when or where.
Does FTM not have a "Yes they died but a date and place are unknown" indicator?
Maybe this was another reason why I stopped using FTM because they did not support a
1 DEAT Y
tag as well as changed the FROM ... TO.... (to a) BET ... AND ...
I use the "1 DEAT Y" a lot when I have no real evidence they died and have nothing to approximate the death other than saying "Before they were 120 years old" =>