Concerned about Grandson’s diet

When my children were small I knew a couple of children with odd diets. It was clear that the mother in both cases was to blame.
My attitude is that you simply allow children to choose what they would like, not forcing them to eat anything in particular. If a well balanced meal was put in front of them and they didn't want anything you offered, that was fine. No substitutes allowed. Only drink offered was water. Worked with one of them, the other child's mother always gave in and he was a sickly specimen.

My son only ate Ready Brek, crisps, Angel Layer cake and Bourbon biscuits until he was at university where he met a girlfriend who cooked spagbol for him. Never looked back after that.

My girls were picky, my boy ate and eats everything in sight - I served the same meals regardless. When they were very young, so under ten, they were allowed to have two foods the refused to eat, and of course, anything which disagreed with them (my son cannot stomach liver, makes him violently sick) They all had their two really hated foods, and ate everything else - only a little if they didn't like it but they ate what was on their plate. I could not afford to cater to special diets and could not afford all sorts of processed foods. Crisps et al were treats in my home. They all ate and eat what is put in front of them. The eldest unfortunately has an illness which means she has a very limited diet now, and often reminisces about "eating a bit of everything, even if you don't like it", as she says she misses the variety. Personally, I think it is insane to allow a child to dictate their diet to that extent. If mine refused to eat something, they didn't eat it, but got no dessert and no snacks until the next meal.

Gave him the delicious dishes that I have described below :
Like Samosas, bread pudding these both can do much of your work.

Samosa recipe :
www.recipestrack.com/2020/02/samosa-banane-ka-tarika-samosa-recipe.html

Bread Pudding Recipe
www.recipestrack.com/2020/05/bread-pudding-recipe.html

Earlier poster mentioned sensory disorder. One GS has that and eating many foods is nearly impossible. Dr. said to continue putting small portions of foods everyone else is eating and very slowly his tolerance is improving.

Sure it is not ideal but if he is healthy then he’s probably fine. If his doctor isn’t concerned that is. Are his parents giving him vitamins? This way you’ll be reassured that he’s not missing out on important vitamins and minerals.