The family of these that I am helping say that Dennis middle name was Hare but looks like it was really Harry
As mentioned - there are 2 births in 1926 - only one has a middle name of Harry
I am guessing that you are making some assumptions here as the info you are giving appears to be based solely on what you have found on freebmd rather than actual fact.
What is this persons connection to the person you are helping? Do you know for certain that he had 2 brothers whose names you mention above or are you basing that on a freebmd search of Parsons/Waller births?
The son born in 1931 may be still alive so you need to remove his details from your reply