The new spouse and her already-adult children were insufferable. She wanted it clear that she was the love of his life and that her family meant so much to him.
She was already getting the house and demanded equal time at the funeral service for her children and equal mention for all of them in the obituary.
They threatened to leave the 1st spouse and children out of the burial service and not attend the funeral (no big loss on the last one). The original family decided that it doesn’t really matter in the grand scheme of things and gave them what they wanted, but it made a really somber situation a lot harder.