Here are a few things to try:
Macaroni and cheese (homemade, with the less sharp cheddar cheese)
Ensure...comes in several flavors
Ice Cream...it was one of the few things I could consistently eat while on chemo
If the patient can tolerate some ice cream, you may want to make a milk shake using some Ensure and some ice cream.
If he/she is not experiencing nausea, the lack of appetite may be due to depression. If that's the case, he/she may need to treat the depression as well as the cancer.
Good luck. It's very kind of you to be looking for help for your friend.