We also would not accept suits for burial! I think that is outside the scope of what a general clothing closet should be.
In my opinion, if people want to donate suits for burial, they should either go to local funeral homes OR the Decedent Affairs office at your facility. I will say in my 10 years here I've never had anyone (internally or a patient's family member) inquire about needing a suit, nor has anyone tried to donate one for this purpose.