After affects from chemotherapy.

Hi, my fiancé was diagnosed with stage 4 colon and stage 4 multiple tumours on his liver in September 2023, non curable, no offer of surgery but hoping to manage it. He has received six cycles of chemotherapy, intravenously and orally, the results came back in February this year showing the cancer has shrunk in his colon and liver so treatment stopped for three months, more bloods another scan and see in three months if it has stayed the same or grown. My fiancé is so nauseous, feeling out of sorts, lethargic, just not himself more often. Is this normal after affects from the chemotherapy ? Any help or advice would be greatly appreciated.