Should I be upset with my friend? Or just let this particular incident go?

I invited my friend to a baseball game last week (which we would had gone to today). My parents are season ticket holders and are out of town for a few weeks. He said his sister and her husband were in town this weekend but he said he was interested depending on what was going on and would let me know. Saturday night I hadn't heard from him so I sent a text saying "So I'm assuming its a no for tomorrow? If you can't, we could always do next Saturday." He wrote "My sister is leaving tomorrow morning, I'll make a game time decision tomorrow. But next Saturday sounds good too!"

I didn't want to seem like that "pushy" friend, so I decided I would just wait for his response. I got nothing. So at the last minute I had to sell the tickets because I got no response (they didn't get sold so my parents lost money). I'm thinking he thought there were other people going too, so didn't realize I would have to sell the tickets?

This obviously caused a major inconvenience. I know part of this is my fault for not being more assertive in texting him, but I thought he would text me when he would know. Do you think he assumed that if he didn't say anything that he just wouldn't go and I still would? Should I say anything or just drop it and invite him to the next one?