Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
There is no text to prohibit holding a walimah (wedding feast) on the side of the wife’ family if they want to express joy on occasion.
In responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
They are right in saying that Walimah (wedding feat) is the responsibility of the husband; they are the ones to host it. However, they are wrong in telling you cannot hold another function to celebrate the occasion – after the Walimah.
In Islam, calling people over to share meals on happy occasions is a good thing. No one can condemn or declare it as unlawful. People are free to do so; according to the rules of jurisprudence, ‘Things are permissible unless forbidden.’
There is no text to prohibit holding a feast on the side of the girl’s family if they want to express joy on occasion.
You can show them this answer; if they are still not convinced, you can ask a qualified scholar.
So, I would urge you not to quarrel over this issue and focus on making it a joyful occasion asking Allah to bless the couple with a happy marriage.
Almighty Allah knows best.