What is the family compatibility?!
Question: Mother - Libra
Father - Sagittarius
Grandfather - (My mothers dad) Pisces
Answers: Mother - Libra
Father - Sagittarius
Grandfather - (My mothers dad) Pisces
Compatibility, especially among family members, is so much more complex than the Sun signs of the members...you really need full charts, or at least aspects to get a good picture of the interactions.
Very generally, based on Sun sign only, the mom is going to try her best to keep peace between the Father and Grandfather when they argue, if ever..I could see the grandfather being intolerant toward the father Sag's optimism and perhaps criticizing the Sag's belief that "everything's going to be okay"....mom would basically try to take both sides and it would make her unhappy...
Again, without knowing the aspects involved, it's really hard to be more specific or to see what "mitigating influences" are in their other placements.
Blessings to you
Mother and Father are compatible. But Sagittarians and Pisces aren't suppose to get along very well.
Its family...no matter what they get along.