figure out how much fiber and protein you need (minimum effective amount) and get that daily...but don't add extra protein and fiber if you're having a hard time getting all the cals. these things keep you feeling fuller.
get tons of healthy fats.
you could make a portion of your calories into a blended shake and drink it, when unable to chew/eat.
you could also look into AP, Prime, or anabeta....these separately, or in combination, always make my ability to eat go through the roof.