I love how thoughtful Charles is in all this, it's not his counterpart he's ultimately worried for but all those who would be effective by the loss of this world's Charles Lee. I honestly never thought about what would have happened if Moth!Charles died and FW!Charles was to disappear.

I'm sure Haytham, being Connor's father and probably mentioned somewhere in Charles' will, would step in. This world's Connor was an enemy of the Order and now their prisoner, doubt they would let him go so easily. Haytham could just marry him off to another Templar.

Though I do have a feeling that FW!Connor is shooting himself in the foot here by letting Moth!Charles live. Wonder what ultimately drives him into killing his counterpart.