Hi iglekott
That is so sad. I suppose you must be absolutely certain he is dead not just curled up. It must have been a horrible shock for you to find him. As you say, he may have been old and there must some hedgehogs who die from natural causes and maybe he was one. But when we have known a hog for a while we can get very attached to them and feel very sad when they die.
There are two links which you may be interested in regarding dead hedgehogs.
https://www.hedgehogstreet.org/help-ive-found-a-dead-hedgehog/
https://www.hedgehogstreet.org/garden-wildlife-health-gwh/
With regard to the box. After you have cleaned out any bedding and I would either burn it or put it out with your household refuse in a sealed bag as there may be parasites in there. Then thoroughly clean out the box and use boiling water and make sure it gets into all the cracks, so that it kills any parasite eggs. Don’t use any chemicals because most are not good for the hogs. I had a rat who died in one of my hog boxes and I did as described. I have since been using it as a feed box, but there has been no problem with hogs going in there. It’s up to you whether you feel you want to relocate the box.
Maybe leave the box for a day or so to make sure it is completely dry again and then if you are hoping another hog will nest in it, maybe put a small amount of material in the box to start it off and lots of other material nearby so any hog can take in what he/she wants.
If there is one hog there, it is possible there are other hogs in the area and hopefully another one will find you, if you keep leaving food and water out.
Good luck.
