Iacismma – it doesn’t necessarily follow that the reason she would set him up with her friend instead is because she thinks he’s not good enough for her.
Even it is, I’m not sure that’s a problem. If I don’t think a guy is Frum enough or smart enough for me, why shouldn’t I set him up with a friend who is less Frum or less smart than me? (obviously one has to be very careful how they go about it so the person isn’t offended, but if one could do it in a way they are sure the person won’t be, I don’t see the problem).
On the other hand, if there is a real concern that the guy may be a bad influence on the friend, then it may be assur according to halacha. There are halachos about not setting someone up with someone who you think might be bad for them.