When will food taste good again after chemo and radiation?

My husband was diagnosed with a Stage 4 bladder tumor in early Feb of 2020. He started with 4 rounds of chemo in March and a heavy dose of radiation in March, at Mayo in Rochester, MN. After they determined this was the correct treatment, he began 5 weeks of daily radiation concurrent with Cisplatin chemo two days of each of those five weeks. He never felt nauseated. Never got sores in his mouth. However, his taste buds went haywire. Everything under the sun tasted disgusting.

The odd thing is that he is now just about 3 months past his last Cisplatin chemo treatment and radiation, yet his taste has gotten worse. He can't stand even looking at food. He has dropped 25 pounds since treatment started. The dietician told me to give him six small meals a day. He can't even stand to put something in his mouth once a day.

Sometimes I can get a quarter cup of cottage cheese with canned peaches in him. Other times a half cup of mashed potatoes. Bran cereal in the morning. But no matter what I try he says it's torture getting it down because it all tastes so terrible. I am having him drink Boost 20 gr protein drinks 3 times a day and an considering pushing 4 a day on him. He hates them, too, because they are way too sweet, but he can gulp them down quickly. However, he has to immediately follow the drink with three green olives, to get the sweet taste out of his mouth.

I've tried everything... gargling with water/baking soda/salt before eating. Gargling with black tea before eating. Giving him sauerkraut and other non-sweet foods. (He absolutely hates any meat because he has to chew it). I've given him bean with bacon soup but I have to puree it first, so he can quickly drink it down.

I've been on the phone so many times with dieticians and doctors from Mayo, and they all say this won't last forever. But when his treatment ended they said, "Expect another month or so when your taste is still bad." It's been three months, and I swear, it's gotten worse the last few weeks.

Has anyone ever gone this long with tastebuds totally messed up? My husband is beginning to think this is going to be what it's like for the rest of his life!