What should I do when my fiances parents REFUSE to spend any money on our wedding?

My fiance and I are getting married next year, I know it's mainly the brides parents that pay for the wedding, but the grooms parents should pay something as well, especially if they expect to be able to invite 32 family members! But my fiances parents absolutely refuse to spend any money whatsoever. They claim to not have any, but we know they actually do have plenty to be able to spend a fraction of what my parents are having to spend. His parents just seem to think it's ok that my parents are paying for this entire wedding. My fiance and I are paying for certain things to, I just can't get over the fact that parents wouldn't care about their ONLY kids, not just only son or whatever it's their only child and they don't give a crap about his wedding. It's so ridiculous. Idk what to do because we can't afford a ton of stuff, my parents can but thats not fair to them to have to pay for EVERYTHING