Maybe if you go through with him on a list of snacky veggies he can eat, he can pick out those he prefers over the others. (I know I'll starve before I gnosh down on raw carrots.) I do wish his wife were more supportive in these early stages. If she needs to consume those things he loves and can't have, she could at the very least do it out of sight for now.
I feel bad that she won't at least try to work with him on meals and meal planning. At least you should be able to give some ideas. But if he's never cooked for himself -- that's a major road block, especially given the wife's apparent attitude. Have you known him to take on hobbies in the past? If so, perhaps he could consider cooking a new hobby? (Don't know if that would work but everyone in my immediate family cooks, male and female alike.)
I've been texting him today, and the first thing I told him was, "Let me know if I'm annoying you with this stuff, but here's some tips," and he hasn't told me to stop, but then again, he wouldn't even if I were.
About 20 years ago, I got up close to 240 lbs and was diagnosed with type 2 diabetes, and one of the things my insurance paid for was a week-long course in nutrition, and that really served me well. I lost over 70 lbs in one year, so I not only have some understanding of basic nutrition, but I also understand going from not knowing diddly-squat about food to having to be a little savvy about choices, and what it's like to go from eating anything you like to having to live with significant restrictions.
He can eat eggs, so today I sent him a very plain-Jane version of shakshuka, and he turned his nose up at that. Apparently, he likes tomatoes and onions and bell peppers and eggs, but not at the same time.
He also likes canned tuna and tuna salad, so I sent him a recipe that uses low-fat tzatziki for the dressing, and that didn't win any approval, either.
I told him that he's got two changes coming up - make more food from scratch and broaden your palate, and I got the crying emoji back, so he's going to have to come around.
He's not a cook at all. He can't even make stuff like Hamburger Helper from a box. His diet has always been restaurant food and junk food. He once made me nachos - Fritos dumped on a plate with cellophane-wrapped fake orange cheese on top, stuck in the microwave...and he was really impressed with himself.
As to his wife...after 15 years in the family, and giving her every benefit of the doubt, I can say I just don't care for her very much, and I don't think they even make a good couple. He's always had the absolute worst wives and girlfriends, because his number one priority is his life between the sheets, and as long as that's ok, he'll endure anything else.
Apart from her libido meshing with his, he's outgoing, she's introverted, he's a pleaser, she goes out of her way to irritate everyone around her, he's a touchy-feeling romantic, she's an emotionless stump (apart from the sex drive), he loves to spend money and give gifts, she's a tightwad, and on and on.
Where that lined up with this is that he's a very empathetic person, and when someone he cares about is in trouble, he's the first one to help, and to really try and be emotionally supportive. She's not. She's (by her own admission) fairly hard-hearted and seems to have taken the position of "that's his problem to deal with, not mine."
She's also not a cook at all and gets by on booze, weed, yogurt, and raw fruit & veg. I do know, when I asked if she was having any problems helping with his diet, she laughed sarcastically and said, "I'm not doing any of that! Were eating separately!" That's how you end up when you think with your Richard.
He's retired and he's a hi-energy person, so I'm going to try to get him to understand that cooking can be fun, and he gets to eat the results, and he has the time on his hands to do it if he wants. Right now, I think he's fighting the idea that he can't just open a can of pre-made healthy food and zap it in the microwave and be done with it.
Yeah, the great nephewlet's gifts was sent via Amazon three days ago, and my niece's gift was dropped into the box before I retrieved her gift to me - and note the new addy in the return notice portion of the package. Being Sunday, there were no postal workers there. (Well, here we only have a lone postal worker.)