I man, some humoring is perfectly fine. We don't want to alienate his supporters. If that means being the bigger person, I have no doubt Hillary will be as gracious in victory as she was in defeat. So, giving him token things he wants is perfectly fine.
However, there is a line, and he has to realize that if he gets too close to it, he's going to get shocked. He doesn't get to have a say in her Veep selection. He doesn't get to determine the platform. He doesn't get to determine her cabinet. A few things to give him the illusion of having some power over the convention? Meh. Fine. no worries.
The moment she has 2383 delegates, though, the media will be 100% done with him. He can wag his finger all day long and no one will pay him no mind. How he wants to land the plane will be up to Bernie.