Is it possible to make an agreement, like that he gets 20 minutes to color or have books read to him each morning, or that he gets to watch a favorite TV show once a day while having a snack he likes? Maybe if it was routine and dependable, it would help him regulate a little bit more easily? That being said, it probably wouldn't be helpful to offer such things unless you could be fairly certain you could deliver on it with very few exceptions. (I'm not multiple but have a very close friend who is, and if we promise that, say, I can do a phone call with one of the littles, it is pretty disastrous if it has to be postponed for some reason. Small children take disappointments very hard!)

Also, I don't know what your inner world is like (if you have one), but are there things that could be created in the inside world to keep him a bit happier? Blankets, a teddy bear, toys, a tree to climb or a swing? Not everyone's inner world can include such things, but if you have space inside for things like that, it might help.