Did families have relatives on both sides of the civil war?

Yes. Because if you think about it, if the family lived on a different place then theyd still have to fight against each other like the "brother on brother". They were both brothers but battled against each other.

If you are talking about the American Civil War, then yes! This mad the war very had to fight, since families with different opinions on the American way of life were pitted against each other in America's bloodiest war.