Why does my husband always belch rotten egg smell after he eats every meal ?

Some foods and drinks cause foul-smelling burps, like eggs, meat, and dairy products. Carbonated drinks and beer can also cause belching due to the release of gas in the stomach. It is important to note that persistent and frequent belching with a foul odor should not be ignored and requires medical attention. https://metrogi.com/news/why-do-i-get-sulfur-burps-and-how-can-i-prevent-them

It is not normal to have foul smelling belching after every meal. It may be a sign of Gerd or inadequate gastric emptying (Gastroparesis). Husband may want to try a trial of antacids, but if the problem persists, he should see his doctor or a gastroenterologist. Good luck.