Family members can be tricky. They can make excellent opportunities to roleplay for the players. But ... if every adventure turns into "Save Bob's Mother and Father ... again" then the players may begin to resent Bob. Or the Players will turn all of the future PCs into misanthropic orphans to cut off such an avenue of attack. On the other side of the coin, if the villains DON'T go after Bob's dad, then they're purposely avoiding an easy method attack.
So, yea, family members can be tricky.