All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.
If this man is religious and of good character, you are advised to accept his marriage proposal in compliance with the command of the Prophet, sallallaahu ʻalayhi wa sallam, in this regard. Such a pious and well-mannered man is likely to honor his wife if he loves her and he will not wrong her if he dislikes her. You should not refuse his marriage proposal for any other considerations, whether social or financial. Moreover, you should know that denying your daughter to marry a suitable suitor may cause her fall into Fitnah (temptation). Please refer to Fatwa 128966.
Your wife's refusal of that man's marriage proposal for the reasons mentioned is not justified. It is not incumbent on your daughter to obey her, even if she is her mother, because obedience to parents is limited to what is good (for the children), and in your case it is not so. There is no doubt that you should try to convince her to accept the marriage if possible.
Allaah Knows best.