Thomas had always been different from the rest of his family. Better. She had been the only one to see that, and loved him for it. It always hurt her to see how alone he was, because Inari didn't know the truth and she had to admit to herself she wasn't the most stable support system.
But Harry was a godsend.
He loved Thomas just as much as she did (in different ways, of course, but the same principle applied), and she knew Thomas was the same.
Maybe, between her and Harry, the two of them could keep him afloat.