The feeding therapist should give you a plan for this. It's been a while but ours went something like this -

step 1 - put the food on the kid's plate, they don't have to eat the food but they can't remove it from the plate
step 2 - they have to touch the food to their lips or maybe it was their tongue, hard to recall
step 3 - they have to put the food in their mouth but they can spit it out
step 4 - they have to take a small bite and swallow it, just one bite
step 5 - work up to more bites

You work up slowly through the steps. It really did work.

So it sounds like your son is doing amazing in feeding therapy. For reference my DD would need like 3 sessions to even touch a new food. The idea of her eating 6 non preferred foods in one session is, wow I would be so happy. Agree to talk with the therapist but also be really sure you haven’t turned meals into a power struggle. As long as you stay relaxed he will eventually decide he likes these foods and eat them at home.

What does the therapist say about that pattern?

Have you tried doing the visits virtually? That may allow the therapist to get a better sense of what is going on in the home environment during mealtimes without requiring an in-home visit.

DS3 tries and eats almost all of the food (I pack 6 different kinds) that he refuses to eat at almost every single feeding therapies for a few months. The feeding therapist plays games with him and he says yummy. Those are the exactly same food that he refused to eat the night or few days before at home. There are meat, tofu, fish, veggie, and other things that I cook and he just refuses to eat the second he sees them on tables at home.

I feel suck, but I am not going to spend time to play food games with him at every single meal at home. We are going to figure out why he acts differently at home compared to at feeding therapies, maybe I will invite the therapist over to my home for dinner one day......