Feels like a brick in my lower stomach

Most of these types of issues are well handled by acupuncture - particularly issues where all western medical tests are inconclusive. So in general you should consult an acupuncturist in your local area and if it’s going to help you you should know within 4-8 treatments more than likely.

But to try to help more, I have a couple questions:

So just to be clear you mention he feels this “above his right leg”, but then you mention he has a “brick in his stomach” - on most adults this would be potentially at least 9 inches or so away from eachother - so can you describe the pain in relation to a body mark perhaps - like the belly button. Where did they do the CT scan?

Generally pain above the leg in the lower abdomen would be an inguinal hernia - a common ailment in middle aged and beyond men. Usually there is a somewhat obvious pouching out in the groin area but depending on any number of factors you may see nothing. The discomfort, however, can come and go.

Other issues could potentially be some type of bacterial issues in the colon that come and go creating bloating, etc. that ends up feeling uncomfortable. Generally, if this is it acupuncture, possibly with Chinese herbal medicine, would likely be very helpful.

Has he had a colonoscopy at anytime in the last few years? And, if so, did they find anything?

For an acupuncturist, you appear to be in the UK, so regulations are minimal. Generally you want a fully trained Chinese Medicine practitioner (ie not an MD or other health practitioner who also “does acupuncture”). You should find someone who practices the full gamut of Chinese Medicine - acupuncture, Chinese Herbal Medicine, and ideally tuina - Chinese medical massage.