First order of busness, imo, is get rid of the junkfood...babies don't need cheese doodles and fries! Blecht!! :-)
Second...continue to offer only healthy nutritional food. It's summer, I can't imagine he doesn't like watermelon, honeydew or cantelope...cut up into "his size perfect size".
We give Ava, our 14 month old (and gave our other 2, also)everything...avacado, raspberries, blueberries, blackberries, mango, strawberries, she has grapes cut up really small and I remove the skins, peas, beans, corn on the cob...all sorts of stuff, tell your friend to really use her imagination with him and food...
My daughter at that age started with the "spoon business". I gave her a spoon to hold while I fed her - that lasted for a while, now, she likes to do it all herself - which of course, I hate because of the mess...but that's just a part of mommyhood that whill never go away!
Tell her to hang in there and try all sorts of new fruits and veggies (and new meat, pork shops, turkey burgers, steak)...and stay away from the junk - healthy weight or not..why start the yukky stuff?