Every time he commissions me he wants me to redesign one of his characters for him(regardless of the commission type), and then gives me a drawing that he basically wants me to copy line for line using said character.
I spend more time on his commissions than anyone else, and I don't mind spending extra time on a commission!-- especially if it's reference or something, but he is only ever interested in the cheapest commission option possible so I end up spending hours streaming a five dollar commission to make sure it is copied exactly. That part is what really bothers me- I realize poses can't be copyrighted but I feel very uncomfortable copying another artist's work so closely. Some of them are commissions that he's bought- but some of them aren't, and after a quick FA search it appears that he has dozens of the same posed commissions over and over(so I'm not the only one he's asking to copy art), which leads me to believe that the original original works are probably not associated with him at all.
I'm not really sure what to do here. I'd like to edit my TOS and also explain to him that I will not copy drawings for him- is this reasonable? The poses are nothing particularly unique, it's moreso how closely he wants them copied that bothers me. I want to be fair to my commissioners but not at the expense of being fair to my fellow artists.
Sorry if this is a little all over the place! Any advice would be appreciated. :)