Sending fattening and steadying hugs.
I've just been reading in your other thread -- Weight Loss and SLO Treatment. Fatty acids such as omega 3's are usually very beneficial for SLO. If you aren't using it already, and if B's digestion isn't too delicate, how about trying a small amount of omega 3 oils/pills? Add a few more calories, and good for his nails. Scout, who had SLO, loved salmon oil on his food.
Theoretically, I'm a follower of the "feed more of what they're already getting." But ...