My FIL spoke to my husband about all the ways they’ve helped him over the last few years with money. My husbands grandma was a hoarder too but she allowed people in the house so my husband went there when he was young. So that was a lot of the basis of my FILs argument. He’s made my husband feel like a disappointment to them which is just ridiculous!
It's also really manipulative. My mother is a hoarder and a guilt tripper. She uses guilt as a last resort when not getting her way, pulling out the 'bad daughter/look how much I've done for you card' when she's unhappy with not getting her way. It's a total bummer. My mother has 8 grandchildren ranging in age from 31 to 6 years old. They never see her house. I grew up without grandparents. So to have a mother- an available grandmother- who has chosen to hoard over being a loving, living grandmother, has been an incredible source of pain for all of us. She has grandchildren who literally live nearby and don't know her at all because inanimate shit taking up every corner of her house and garage has taken precedence over loving her family on real terms. Pictures of her grandchildren on her mess of a fridge is enough. Her hoarding stems from her own pain. I am so sad that, at 84 years old, she's not ever changed. It was very stressful growing up with her but because of my dad, the hoarding was not allowed to get out of control. It got worse in later years and it's become impossible since my dad died 16 years ago.
My eldest is 18. The last time he was in my mum's house, he was 3. Of course he's seen her over the years because she has come to stay with us. But we're never allowed to see her on her turf.
But I remember when he was small (he's the only one of my 3 who has been inside her house), the choking hazard (from all the shit like staples, screws, bits of glass, paper clips, embedded in the carpet) was just unbelievable.
I see there's a hoarder on this thread. Get help! You can justify your actions all you want, but it's misery for others. And here you are OP, your DH is the 'bad guy'. Unbelievable. But if that's the spin your FIL wants to put on it, screw him. How dare he guilt trip and humiliate his own son. I've been there. It hurts. Your FIL is not being loving or understanding here. You do not have to protect his embarrassment. It's his damn problem he's a hoarder. And if he's embarrassed, well, he needs to get help, not dump on others and pass the buck by making your DH out to be a 'disappointing son'. I am sorry to sound harsh, but I put up with years and years and years of damaging guilt. I've spent my entire life worrying about my mother, sleepless and in despair over her. I've been trying to fix her my entire life. I've worn her hair shirt on her behalf and I'm done. Don't let your PILs put their burden onto YOUR marriage.
I am so sorry to get on my soapbox, OP. But the pain of my mother's hoarding has been a heavy burden. If I were in your shoes, I'd use this as a perfect time to reach out to your DH, who will be carrying around a lot of unresolved shit thanks to being raised by hoarders. This is a great opportunity to purge himself of the guilt he's carried, the shame, the anger, the sadness. Sorry if I've gone off on a tangent. Your post touched a nerve. 
But I've been there with the baby in the hoarder's house and it's definitely not worth the risk.