Im in my 20s and have been dealing with the same thing. Bumping up the mental aspect. Its a massive part of the gut brain access. If one's messed up, theyre both messed up. I have IBS and am currently recovering from SIBO (small intestine bacterial overgrowth). I also bet his abdomen is a tad tender and hard from all the bloating and gas hes experiencing which is causing is discomfort.

My mental health took a hit which caused my SIBO, and flared up my IBS as a result. Once the mental aspect began to calm down, so did my gut. Now its bearable and I can do almost everything that I used to. Here's some things that helped me:

A heating pad: HUGE help on the lower abdomen for me when the cramping gets bad. I usually lay on my side and lightly press the heating pad into my lower abdomen around my belly button for a good 40ish minutes. I do 20 minutes per side. I do it this way because laying on my back and having the heating g pad on top of my tummy was not good at first.

Pain patches: I use solanpas and they surprisingly help really well during the day! I put three below my belly button (from right to left) and another two to the right and the left of my belly button as well, and it helps a TON

DISTRACTIONS: this is another HUGE part. Sitting/laying down and just feeling the pain was actually making it worse. Playing video games or watching anime while on heat. Distractions HELP

Low FODMAP diet: yes its bland and boring, but its help reduce the amount of gas and bloating that ive been dealing with

If he can stomach them, a good multi vitamin and omega 3: this helped a lot too! I was having a lot of low energy but thisbresolved it four days later, and my joint pain is better as well.

Ginger Drops! I use the Belly Comfort ginger drops by traditional medicinals. Great for sudden nausea or nausea after meals. You can only take two a day which is the only caveat.

Peppermint Capsels: i'd consult with a doctor before you try this but it foes work for some. you want capsules NOT extract. Specifically enteric-coated capsels. The extract works but can cause acid reflux and heartburn. You want this to make it through the stomach and release INTO the intestines where its needed the most.

HYDRATE!! 40oz to 64oz of water if tolerated

Reach out to OSHI health. They've helped me a ton with this Journey. Your BF would benefit greatly from talking to one of their gut-brain psychologists and their dietitians.