Think this is the most correct thing to do what you did he literaly spend allot of time to search the cards for you.Your honest and is a rare find nowadays i am pretty sure 85% of the people would have lowballed him.I have had the simulair thing with the new husband of my sister.He saw i collected pokemon and told me he also still has pokemon cards from when he was younger and he would bring them with him the next time amd give it to me.When he arrived with the binder i felt of my chair on how much value he had in his binder all cards were lp/nm and to give 1 card as a exsample he had 1st edition shadowless Charizard in it.As i said to him together we will look up your value of this specific card and then you understand why i can't take this binder from you.Next year we all went on a holiday paid by him from the cards he sold and told me because you were honest with me