It was beyond tiring to look after someone twenty-four seven, but it was his duty to do so. The only question that consistently reappears is whether being overprotective would be the best thing for her or not.
It wasn’t about letting go of the child (because she doesn’t belong to him), but about the best course of action for her specific situation. She was kind, almost too kind, but shrewd enough to know that returning cruelty with kindness will eventually break either their stubbornness or her beliefs, and she’s never lost before.
So just this once, he takes a gamble on her potential. Just one time is all that’s needed to establish what kind of person she’ll become, and for the first time, he’ll stand by and watch, no matter what choices she makes. She’s old already, and he’s not perfect, but they’re both better off this way.