No, that’s not right.
A proxy gives a person the right to vote at a meeting. You do that on a proxy form. I am not sure from what you say whether there was a valid proxy.
A proxy does not give the holder the right to nominate for election to the Committee.
Nomination for the Committee is a separate matter and must be from an owner, either in person or in writing. (note it could also be from an appointed legal representative but let’s leave that) So it has to be the owner specifically saying, I nominate X for election to the Committee.
So from what you said the son was not validly nominated.