We have a cat that is 13 years old. He likes peeing in the house off and on, usually on blankets or in the dog cage. He does not do this all the time. We do have 4 cats in the house but 5 litter pans ...
With all the litter pans I suspect it's more a dominance issue. He may be marking areas to claim that this is his domain. He may be telling the dog and whoever is using the blankets that this is his property so to speak.