DS eats fruit extremely rarely, a sliced apple maybe & the occasional glass of juice.
He does eat almost every vegetable possible though, so I make sure he has plenty, extra veg sticks with lunch and a variety of veg with every dinner.
Keep extending the veg selection, add raw veg (peppers, carrots, cucumber, toms etc) and keep adding to the hot selection, add cabbage, swede, cauliflower, squash, green beans, sweet corn, stir fried bean sprouts, pak Choi, keep adding. I find it best to have a small quantity of a variety of veg with each meal, including ones they've previously not been keen on. If they're not keen on one, they may eat the others. & change the cooking method, sometimes a knob of butter makes a veg more palatable! You can always reduce the butter quantity later.
I think it's fine & he is very well.