The charge seems high for a pillow + pillowsheet.
I don't know what the actual language of a hotel is on these things -- assuming it was in the course of a normal stay and normal activities, it does seem petty for the hotel to charge to replace the pillow + pillowsheet instead of just eating the cost on their own.
After all he could've done the less honorable thing and just hid the pillow and it might not have been noticed until they went to wash the sheets later or a future guest arrived.
That said I don't fault the hotel for immediately throwing away the pillow + pillowcase and in fact I applaud them. I have no interest in a sheet with blood stains on it -- no matter how many times it has received industrial washing. I see a blood stain on my sheets upon arrival and you better believe I'm calling the front desk to immediately replace the sheets and not pleased about it getting through the housekeeping staff (happened to me this year at the Ren Barcelona Fira when they changed the sheets during my stay and put on sheets with blood stains).