How to live normaly with Irritable bowel syndrome?

What meds has he been given, if any and if so, any antibiotics?

He needs to get at the root cause. IBS is a symptom. But in the meantime peppermint tea helps with cramps and pain. Mine started from gallstones. Unfortunately, it's a long road and a mystery for many. It's a lot of trial and error and has to be dealt with on an individual basis. Try different diets and/or maybe a fiber supplement to keep things stabilized.

Hi,
I'm very formiliar with those symptoms, my digestive system rules my life, or it tries to.
Find a decent Gastrologist firstly as many things can be the cause. Get all the test done to eliminate what is not a problem. When or if they find nothing don't accept it is in the mind, push on for answers.
I take Omeprazole and Domeperidone, at least 30 minutes before eating, along with Laxsol. I don't notice the difference until I stop taking them, then the difference is obvious. I may take Gaviscon after a meal when the fire in the stomach kicks off, if it is mild then a gingernut biscuit with my cup of tea, always dunked, isn't that the only way to eat them!
For food I'm stuck with wholemeal bread, cups of tea (don't like water) and am limited to the total amount of food I can eat or drink per day. My fear is I'm slowly starving myself.
For breakfast I have only a cup of tea, lunch it could be a boiled egg or a shaved ham sandwich and for evening meal possibly a small pice of grilled chicken or fish with carrot and or sweet patatoe, alternatively 2 boiled eggs or the ham sandwich. I drink a cup of tea six times a day and always after food consumption. As I suffer constipation I eat 1/2 dozen prunes around mid day, if it is a bad day I might have canned peaches in the evening which seem to help with the constipation, when really bad I will add bran flakes to the peaches.
I find that anything I eat or drink causes stomach pain initially but the tea starts to soothe shortly after. I can also eat a gingernut biscuit, the ginger helps soothe the stomach nicely.
I stay away from most everything else and refrain from preprepared foods off the shelf. No salt, no sugar, no herbs or spices mostly and no fun with food!
For me the journey has taken 13 years to find the cause after being told it was IBS. There have been weeks when I have been unable to eat and the odd time when I have been able to be a pig with food!
I have Autonomic polyneuropathy, IBS, CKD, diabetes T2 and some other minor health issues all contributing to my situation, none of which I knew about when my journey started. My Gastrologist agrees with me to eat what ever I can tolerate as some foods I'm not supposed to be able to eat I can, like raw onion, while my home grown foods I generally can only eat cooked which seems to weaken the toxicity to me. There is no ryme nor reason to what my stomach will react to but in general I try to stay away from medication other than what is really ness for the gut as I react to most anything and definitely stay away from man adulterated foods or drinks. I try to eat a vegitable at least once a week but have to be careful as things like lettuce or green veg don't do well in my gut.
If you haven't tried it a good start is the Fodmap foods, they don't always work but it is a start.
If you start noticing bloating of the abdomin immediately after injesting anything look into SIBO, small intestinal bacterial overgrowth, it is many time worse than plain old IBS, but is generally treatable.
That is what I need to do to get through the days, we each have to find our own pathway as we are all different and react differently to what we injest. There will be times when the last thing you want is to hear another Dr spouting on, but remeber we are our own best advocates, keep pushing as the squeeky wheel really gets the oil. leave a Dr alone and they willnot even consider you anymore than the 15 minute appointment, if you are lucky. Generally out of sight and out of mind. The irony for me is 13 years of pushing to get an answer and finally I have some, but now I stll get the same reaction as it is untreatable and incurable, so they can't do much anyway. But at least I know what I'm dealing with now, this has done a lot to calm the stress of the inponderable while the struggle continues.
Cheers

Has he had a cta of his abdomen? Has anyone mentioned possibility of Mals?

I also have IBS and I think my mom had it too. For many years, I thought I was allergic to food. Nothing agreed with me until I tried homemade chicken rice soup every night and found the right doctor in Taipei. By the way, my doctor does consultations with the Mayo Clinic. I’m very grateful I found her because her medicine has helped me a lot. I couldn’t eat oatmeal until recently but because of my doctor’s medicine, I can now eat it. By the way, I no longer eat whole wheat bread because it makes me sick. I eat batard bread which is more like white bread with a sourdough taste. I put a very thin slice of natural cheese on it with no mayonnaise or anything else. Just plain. I eat no sugar, processed foods, etc. This diet has also been very good for losing weight. This has been a bonus.

I would suggest getting checked for EPI( Exocrine Pancreatic Insufficiency), a LOW Fodmap diet, SIBO, and allergies with a gastrointestinal specialist. Perhaps a thyroid check as well.

I don't have advice but I have the same problem with crohn's disease and ulcerative colitis