What possible reason could they be giving my grandpa a second colonoscopy? He had his first less than six months ago

Hi again, kacy_leigh!

The doctor or doctors might have thought when they did the first one that because of some things that were noticed that it would be advisable for him to have a second colonoscopy after a certain number of months had passed.

By having the examination, it's a preventive measure to make sure that there isn't something wrong going on and if there is, they will be able to do something about it in a timely manner before things get worse.

Hopefully, others will be along to address your question. I'm sure that there will be those here who have undergone the procedure.

Thanks!