OP I am 47 and I still don’t like most fruit or veg. I have real textural issues with both.
The truth is that sometimes you just can’t push it so you need to look at other methods:
For my part I like raw veg better than cooked. Carrots, peas in the pod, I will eat carrots cooked but they have to still be crunchy.
I like baby sweet corn because this is also quite crunchy, I can’t stand anything that is soft .
From a fruit perspective I will eat apples, but other than that I drink fruit juice although it has to be smooth.
Soups are also your friend here. You can pretty much put anything into a soup, and then blend it. In the case of e.g. tomato soup, I blend it and then pass it through a sieve to remove the seeds and skin.
Fagitas also work: but instead of salad etc dice the chicken small, then cook, and then add a couple of small diced onions and peppers. Mix in the fajita sauce and you barely taste the veg.
Ditto with stir-fry. Broccoli, baby ssweetcorn, sugar snap peas, the list is endless.
Can you make your own stocks instead of using cubes. That way you are putting veg into those which will be absorbed even though you’re straining the stock.
If you make e.g. cottage pie or spaghetti bolognese use an onion, carrot and celery as the base. It’s chopped so finely that he won’t know. Then add the tinned tomatoes which contain nutrients of their own.
It’s taken a long time for me to get there, but tbh if you put a plate of veg in front of me I still wouldn’t eat it. So it’s all about being inventive, but as time passes that just becomes a way of life. Iyswim.