Cara917 - Nutrition is a really important challenge for many of us. Is your father able to swallow well enough to support his nutritional needs? Being able to swallow "some" may not be sufficient to get enough calories into his system. If he can swallow ensure-type liquids, take good advantage and buy the high calorie variety. I use the Wal-Mart generic called "equate". I get 7 to 10 cans into me per day, and I'm using the 350 calorie/can flavors.
Lots of survivors really underestimate their nutritional needs. And getting calories is only part of the issue. Everyone needs a good sampling of the RDA for all the vitamins and minerals. Plus, the nutrition has to taste good and be interesting, and be available, and be affordable. Other than all that - its simple!!
Pour on the total calories up until his weight returns. Work on the balance, taste and availability as you go. Don't worry about a nutritionist with experience in our disease, become your own expert. Start with 2500 calories per day, at least 64oz of water per day and all the vitamins you can get him to take. You can do it. Tom