Why did my boss pretend to want to help me??

I've having an event this weekend raising awareness for cancer. I told my boss about it in passing 3-4 months ago and he was like "Oh, wow, I'll buy t-shirts for your event, just give me the details!"

I sent him the info, the design etc, and each week he's been telling me he's ordering my shirts.

I didn't tell anyone from the event about the shirts because even a couple weeks ago my boss was still saying "I need to get you those shirts."

Soooo...the event is 2 days away and I'm NOT shocked AT ALL that he hasn't gotten me the shirts, so I don't even care to bring it up. HE was the one who kept saying he's going to donate these goods!!

What should I say to him after the event (since I never see him in the office to confront him anyway) if he apologizes for not getting the shirts. I KNEW he wasn't reliable, but I gave him the benefit of doubt and didn't care because I have lots of other donations coming in for the event.

I don't want to say 'Yeah, I knew you weren't going to come through for me!!" or "Yeah, I knew you didn't plan on getting them in the end."

How can I safely respond when he brings up the shirts next week? He didn't need to impress me and act "involved", so how can I respond when he brings it up?