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 is His slave and Messenger.
It is permissible for the parents of the bride to give her a gift when she gets married and when this gift becomes in her possession, it becomes her property. So, as long as she is adult and of sound mind, it is permissible for her to dispose of it by gifting it to her husband or by doing with it anything that is Islamically permissible. It should be noted that Mahr (the dowry) is the right of the bride upon her husband [i.e. the husband should give it to her] and not the contrary; for more benefit, please refer to Fatwa 85873.
However, there is no maximum limit for Mahr but it is desirable to make it a small amount as this is a means for it being blessed. For more benefit, please refer to Fataawa 106818 and 87514.
On the other hand, there is no fixed period in Sharee’ah for the time of the Waleemah (marriage banquet); so the matter is easy. For more benefit, please refer to Fatwa 84827 and 86075. Therefore, you may organize the Waleemah on the same day of the marriage if you wish.
Finally, it should be noted that it is desirable for the husband to organize the Waleemah according to his ability, yet if the family of the wife want to help him in it, then this is permissible.
Allaah Knows best.