My understanding is, he could try to pay someone to do it, but that's going to blow through the money he already has for the materials. He's trying to get people to donate their time so that he can use the material money on materials.Exactly what I was thinking. You get within 3 weeks of opening the school that's been your life's work and HVAC labor is holding you back? Doesn't make sense to me.
I'm not saying he's lying but I think that's a plausible reason or he's going to have to go back to donars to ask for more money.