my mother inlaw offerd to pay for diney trip, my husband says no way.

my mother inlaw booked a trip for me and husband and 3 kids plus herself and my father in law, in all was gonna cost us 2,000 ( room food paln, tickets ) and we need some spending money. well my mother inlaw decided she would pay the 2,000 and we would only have to have spending money that way we could pay off bills and pay our carpayment off and have money aside to move ( i hate this place ) but my husband says no way we will pay for it all he refuses to let his mom pay/help. and she will have the money to do it. my husband wont even discuss it. its just right out no. what would you do/say or how can i get him to atleast talk about it? or should i just let it go?