What other therapies are recommended with folfiri chemo - Stage 4 CRC

What other therapies are recommended with folfiri + bev chemotherapy?

My boyfriend (age 42) was diagnosed with stage 4 CRC in Dec. 2022. (KRAS g13d) Tumor has metastasized to mainly to liver, lymph in abdomen, stomach lining, etc. I would say median size for the tumors in liver are 7cm x 5cm, and there are a lot of them. We don't know how big the initial tumor in colon is, the scope could not go through during colonoscopy. We started with folfox chemotherapy which seemed to have worked in the beginning, but after about 8th session, the tumors in his liver stopped responding. We just received folfiri for our 12th session... and his doc says he is eligible for a clinical trial that uses folfiri as the base, but with the shortage of chemo medicine, not sure if this will happen. =(

His condition lately: Stomach looks and feels very bloated. We also had paracentesis (for abdominal ascites) done last week because he couldn't eat or sleep from the fullness of his stomach... this went on for about 3-4 weeks before getting the paracentesis. Afterwards, his hands and feet started swelling up. Doc told him that it's because he doesn't have enough protein and advised to take protein shakes. Swelling has gone down a bit after keeping his legs up and lymph massaging. But they still look huge. I think his liver is leaking a lot still. He hasn't been urinating much for the past month, but that has improved today. His bowel movements are on the both ends of the spectrum, either constipated or "going" every hour. Low energy on most days, naps 4-5 times a day.

I just want to know if there are any other therapies that can be combined with his chemo so that he can live... at the least, without pain. Is it too greedy to hope for a cure...?

Thank you in advance.