It does sound weird and cruel.
I like it!
On the other hand, what are the odds that he would enjoy himself and possibly end up with his own gear?
Of course, the "invited himself" part could indicate a couple things. If he is a thorn in your side, I could certainly understand. Of course having him "help" with the cleaning and such could certainly dissuade him from inviting himself in the future.
I find it best not to interfere with other folks business, particularly with regards to family (and yet here I am), so you have the best answer to that part in your own head.
I second the reenactor suggestion for the info you seek.