Thank you for those ideas!

Sounds like a 'Salty' eater.
So, he should be fine with Spaghetti Sauce.
You can sneak spinach, broccoli, Garlic, Mushrooms and other goodness in Spaghetti Sauce.
Just make sure that you cut them up to small pieces before serving the Spaghetti.

This sounds a lot like my 10 year old. We thought it would get worse but three years ago he finally started to transition out of his habitual eating. It really happened on his own. We would introduce foods.. have him smell or touch or taste them. He would then pass on it or say he would want a bit more. The more he was around his peers at school during lunch it would peak his curiosity to eat the same foods. He became very overweight as well and still is struggling to lose that weight. I will pray for your family and grandson. I know how how hard the struggles are. It does get better ❤️‍🩹

Thank you for this great answer. It mirrors what my daughter (the mother) says. I do agree, peer pressure (or incentive) is helpful!

Unfortunately, no.