Talk to General Physician on Diarrhea Occurring Every Year

My husband had food poisoning in April 2019, it was pretty severe with 20-25 motions in a day. It led to extreme severe pain in his lower back (left side/left hip) a point came where he was unable to move at all. Anyhow, with medication and hospitalisation he recovered. Then some time in Aug 2020 he again had diarrhea and it eventually led to lower back pain, I repeated the same course of medication and he was all fine. And now in July 2021 he is experiencing the same all over again. He is better as long as he is sitting but as soon as he lays down or falls asleep he is unable to stand immediately, according to him his back freezes and paon pe wazan nahi dala jata. Kindly suggest what should be done to get rid of this annual cycle of diarrhea and pain.