The kid is taking it hard...
He outright asked his Mom is she knew who he was and she said, "No." For a while he's wondered if her dementia had gotten that far, but was afraid to actually ask the question. It's tough to deal with, but he says actually knowing for sure may allow him to move on a bit with dealing with the situation. He went for a drive after telling me he'd asked, and I sat a cried for him for a bit.