I admit I don't know that much about it, so perhaps you can clear up a question for me.
I know a lot of genealogical work is done in the Mormon Church, but people have told me that when a Mormon marries someone with other religious faiths in their family, they go back and "convert" the other family members after the fact.
This can't be true; it would be unbearably arrogant to do so. Right?
and it isn't
The work can only be done for ancestors WAY back - and even then, is only as an offering, as it were.
As Mormons, (Latter Day Saints) believe in Jesus and that everyone continues to live after 'death' = they believe that those ancestors who have passed over - still retain God's greatest gift, Free Will, and they can then accept or reject the offering...