He can still have most things, just low fat versions.
My husband had an infected gall bladder, was in hospital for 2 weeks and then they wouldn't remove it for 3 months as they wanted to be sure the inflammation had gone. He loves chips, crisps, cheese and fry ups, burgers etc.
Heck make tasty, very low fat sausages. Bacon with all the fat removed, or you can buy bacon medallions, poached or scrambled egg for breakfasts.
I made burgers using very low fat beef or chicken mince. 'Fried' onions in a non stick pan with a couple of sprays of One Cal.
Roast dinners made with skinless chicken breast, lots of plain vegetables and low fat roast potatoes. Boil the potatoes in stock and then put in the oven on a hot baking tray. They come out like roasties. Make gravy with Bistro.
Soft ice cream ,the sort you get from a van, is very low fat.
I tried to find a way of making low fat pastry but no success. Then I discovered I could use pizza dough to make apple turnovers.
He also used laughing cow extra light as a spread in sandwiches, toast etc instead of butter or Flora.
There are alternatives for most things if you look.
He was eating baked crisps and was OK with those.
I did