Hi Mariela,
Nice to meet you here on the site.
Yes, in the begining sports can upset or irritate him if he starts too quickly of exercises for too long.
He needs to start off very slowly and work up to a harder routine as time goes by.
It is important to work his abdomen and back to keep his muscles stong. Maybe he could try doing short 15minute sessions a little more often.
He needs to drink a lot of fluids when he exercises so that he does not dehydrate too quickly.
Do you have Pilates exercises where you live? If not, look it up on the internet and have him do some Pilates for the abdomen to give him some core strength first.
It takes a while but he will be able to go back to normal very quickly.
Sharon

What do you mean when you say he got worse? What is happening…is he sore, does he have more frequent bowel movements?

Yes, he has more movements in the intestins and more frecuence. He was going 8 times a day to the toilette, and this week he started to go like 12 times a day...

8-12 times a day is normal to me. For a jpoucher to work out a lot, have him drink a lot of fluids before, during and after working out; we can get dehydrated quickly without a large intestine.

thenk u guys for your advices, you've been very helpfull, i'll be contacting you again as soon as i have more questions, love