Machine translation to English aside, Marge calling him Abraham is just weird. She usually opts to just calling him "grandpa" because that's what everyone else knows him as. Is that a Spanish dub thing? And calling her by her full name, Majorie?
@LustLord No, in the spanish dub they also call him grandpa and Marge was always Marge. If I had to guess, I would say the author took some creative liberties to make the cheating sex scene more shocking/erotic.