Welcome to OCF! Very glad you found us.

First let me start off by saying that Marinol is a waste of a drug...synthetic THC is no substitute for the real thing. Many of us who've used it on these forums haven't had good experiences with it. If you are going to use THC, and I recommend Medical MJ, vaporize some cheba instead of using Marinol. It will help with the nausea and help his appetite.

As far as the nutrition goes, I agree with Cheryl, protien powder mixed with Ensure Plus is a good start as Ensure is light on protien, even with 13grams. With nausea issues however sucking down heavy shakes can be an issue so adding a long chain triglyceride like Olive Oil to it as well can pack in the calories. OO is 120 calories and 14g of fat per "tablespoon" which will help battle the weight loss. I'd recommend mixing protien powder & olive oil with however much Ensure he can keep down as nutrition is paramount. Blending Peanut Butter with it works too.

Best of luck, keep your chin up!

Eric