Your husband needs to understand the futility of trying to keep relatives happy. Nobody is going to help him in his time of need. Maybe you could start by getting in touch with these people yourself so that you are also a part of whatever it is that is going on. Then you could gradually suggest some more economical ways to gift relatives. I am saying this only because you have already tried talking to him.
1.Dry his cash flow by making him to invest in a property preferably with a good emi scheme 2.Invite your inlaws and his friends circle once a year by way of your H birthday to solve your Hs complaint against you.This could force those around them to gift something,thus your H could do back according to that.This would help to release all those free loaders off him.