show some care to him

Maybe you can tell him that you realize that he seems to have some problem with his GI system (gastrointestinal) and ask him if he needs to see a doctor for his own benefit. Who knows what is going on with this guy - maybe he has anal fistula. Early detecting any possible illness is better than just wait. If he just has excessive gas, you may suggest him to take some medication such as Simethicone (may need a preion from a doctor) for relieving it.

Good luck at your working environment!