Please stop forcing him to try the food. Do not make eating a battle. Meals should be a time to enjoy each others company.
Instead offer him very small amounts of what you prepare and IF he eats it, you can give him another small portion, no comments.. If he chooses not to eat, that is fine, just let him know there will be no snacks or dessert till the next meal.
Children are told how to do everything and food is the last thing he needs to battle.
He should have the option of not eating it.
Remember childrens taste buds are very different from ours.. They are still very sensitive and what taste good to me and you, can taste very different to children..Black pepper and onions can be very spicy to a child. Tomatoes can taste acidic rather than sweet.
Also their sense of smell is still very sensitive, so odors can be overwhelming, especially when his face is as close to the plate than your is..
Also the size of the portions can make the food look overwhelming.
Some children do not like to not being able to tell the difference in their foods.. They like spaghetti, but want the control of dipping it into the sauce.
It is your home, so you have to decide how to handle meals.. In our home, I made one meal. I placed a very small portion on our daughters plate. Salad, was a piece of lettuce, some baby carrots, some cucumber slices and some tomato slices. She did not want salad dressing.
If we had tacos, there was some little spiced ground meat, cheese and half of a tortilla folded in half.
She refused casseroles. So I would keep some of the cooked ingredients separate .
The pasta was plain, the chicken was plain, the veggies, plain.. It was healthier food in the long run, because she could not stand cream of anything..
As she got older everybody in the family had the option of a bowl of unsweetened cereal if they did not want was served for the meal.. Sometimes, I did not want to eat what I had prepared.. You know how it is when in the morning you plan something and after cooking it , it is just not what you are in the mood for?
I remember being forced to eat foods when I was a child. My father would scream and yell if we did not" just taste".. I would be sick to my stomach when dinner was about to begin, I knew it was going to be like torture.. One night he insisted I eat something, I kept telling him I did not like the taste, he kept telling me to just taste it and swallow it.. When I did swallow it I vomited on the table. I was so humiliated, because I was not a good girl and should have liked the foods everyone else ate..
I never forgot that feeling.