He's glad you like them. (He'd be even happier if you were willing to pay him a token royalty to use them, but he's very pleased that you are respecting his wishes regarding not using them for commercial purposes without compensation.)
It isn't about you, BTW. He has always had a very clear idea that if someone is going to get paid, even in part, for work that he did, he should get paid for his share of it. He refused to enter the Reading Rainbow Young Writers and Illustrators contest when he was 7, even though he had entered and placed the two previous years, because he read the legalese on the entry form and realized that, if he won, he was signing away all his rights to his story and any derivative works, in exchange for a few books and bragging rights. I believe his words at the time were "What kind of people steal from little kids?"
So he has a long history of aggressively protecting his copyright...
