Complex sentence: Eleanor always stands up to Brittany when she tries to push Jeanette around, and is generally the only person that tries to stand up to Brittany, though the two of them do share a very nice sisterly relationship.
Split into simpler sentences: Eleanor always stands up to Brittany when she tries to push Jeanette around, and is generally the only person that tries to stand up to Brittany. The two of them do share a very nice sisterly relationship.