In my opinion, only close family members (and I mean here PARENTS) should know who someone is going out with. Having friends, cousins etc knowing who you are going out with is a recipe for disaster and has ruined many a good shidduch. If the person was truly worried for your cousin, you should tell them to direct their concerns to your cousin’s parents. But you should definitely not get involved.
And I agree with postsemgirl. Sem or yeshiva background makes no difference. I hate it when people use the description ‘top’ boy or girl just because they have the right connections/ went to the right sem/yeshiva. And just one more nugget of information for girls – just cause a girl went to a high-calibre sem and got the best grades doesn’t mean that this will make them a better wife or mother. A good boy does not need to marry a girl who knows nach by heart. (no I am not a cynic, and I am happily married, and no, I didn’t go to a sem that required me to learn lots of text in depth).
One more thing I just remembered – a boy’s hasmada in learning is not equal to middos. You have to check out both. Focus on the middos in a shidduch and people will have far less problems in shidduchim…