What are the pros and cons of a feeding tube for a 91 year old male?

Just because you can do something does not mean you should. A feeding tube for someone that age is probably not a good idea. Quality of life is an issue, feeding tubes cause a lot of issues; patients get reflux, they aspirate the feeding liquid and they get diarrhea. And it often seems that they don't get much benefit from the nutrition.
You might benefit from hospice eval to explain what other options are available.

I'd read a lot about it and why it's not what you might think. I researched it a lot when my LO got dementia. There are a whole set of risks associated with it, such as infection. I'd ask the professionals about how it might affect survival and what its like for the person living with the tube Some patients are not good candidates due to that physical or mental condition. I'd also look to his Advance Medical Directive or requests that he gave family before he got sick. If he's still competent, he can make the decision for himself.

My Mom had it in her directive "no feeding tube". She was 89 when she passed, healthy other than the suffering from Dementia. My daughter, an RN, said she would never had recommended one at her age anyway.

Daughter is correct, once its inserted, very hard to remove it. And after 3 strokes, what is his quality of life? Why are they suggesting a feeding tube, because he can't swallow? Not being able to swallow is one of the first signs that the body is shutting down. And when it starts this process, food is not digested. Its actually cruel to try and feed a person actively dying.

Doctors have to give you all the options available. Doesn't mean you need to take the advice. What I would do would be to call in Hospice. My SILs Mom was in the hospital and was given comfort care. 3 strokes probably caused a lot of damage. At 91 he is probably ready to go.

My mother was given a feeding tube after a stroke when we were told by several doctors that there was great chance of recovery. Unfortunately, the recovery never came. You need to consult with doctors and find out more about if the feeding tube will help facilitate recovery, what are the realistic chances of that, as well as the risks of aspiration. My mother was fully mentally aware, so once feeding started there was not opportunity to stop it without being cruel. It’s important to know fully what you’re getting into, both in terms of risk and reward

This is a conversation you will need to have with his providers.
As you make your decision please consider the 91 y/o’s quality of life & would inserting a feeding tube prolong the inevitable.
Good luck to you!