I was going to suggest smoothies, but looks like someone else already did
Don't be afraid to get creative with them...you'd be surprised what you can sneak in to a smoothie!
I wouldn't worry too much about meat if he's eating a good amount of dairy. and eggs are great if he'll eat those!
Also, about him not drinking...have you considered letting him have a bottle just for water, to help the transition?
Sounds like he's getting a little better. I hope he continues!