Well, if kefir is a problem for your gut, I would switch to solely using a probiotic. I have never had kefir, so am unsure what problems it could do to the gut.
I take a homeopathic that is primarily used to heal my leaky gut. However, foods high with FOS can heal the gut as well. If you get a product called inulin (miracle fiber), you can add it to your foods such as coconut bread and it will help heal the gut also.
The homeopathic I took is called digestive enzyme liquidscence, however I do not think it’ll be easy to find it on the internet or even a vitamin store. I got it prescribed to me by my naturopath doctor and don’t recommend the use of homeopathic medicine because I am not a doctor myself. However, any bitters is an alternative way to heal the gut, and you should try to get some if possible. Orange bitters, lemon bitters, spanish bitters, swedish bitters, grape bitters all work. I wouldn’t worry too much about any small amount of alcohol found in the bitters because your body should be able to recover and get past any negatives in the alcohol.