"He doesn't really count any more because he's so deaf."
Have you ever thought this way?
If you have you ever made or felt like making this sort of remark about a deaf person, it would probably help for you to understand what lies behind it.
Why the problem
It is very sad that people who are deaf all too often give the impression of being stupid because they don't react normally to what is said to them. Of course the reason they don't react is because they haven't heard. Or perhaps they have partially heard but missed a keyword - which they often guess at. If they guess wrongly, they don't respond as you would expect, but this is clearly nothing to do with being stupid. It is more likely due to not being sufficiently assertive to keep on asking for things to be repeated more clearly. Deaf people can tell when their needs are annoying the people around them. So they guess or opt out of conversations which is sad.
How to change your mindset
Just to confirm that being deaf is not at all the same as being stupid, think for example of the composer Ludwig van Beethoven who became totally deaf at the age of 32 but still continued composing and went on to create his most magnificent works. Arguably he was a genius, but quite ordinary deaf people have a lot to offer, once they and those around them find a way of communicating effectively.
So try to communicate with a deaf person: start by reading the page on helping interaction.
More common irritations with deaf people and what to do about them
Disclaimer: The information on this site is for a lay audience and I cannot be responsible for errors or omissions. The views, strategies, advice and suggestions etc are based on my personal experience and are not necessarily appropriate for anyone else. They should, hopefully, stimulate individuals to develop their own strategies.