Homeowner vs friend

at first a friends ask me to help him fix little things in his illegal extended part of the house. after I started the work he ask me to help him break down that part of the extension to rebuild a how new extension with permit. I refused to do it because it became to big. I begged and bagged because it cost to much for them to hire a contractor. So I agree to help him but do it myself, I help them find contract to do most of the work. I had to take time off work to help him. I will do the finished work. Now that its down, he decided he doesn't want to back me up to continue his project. He had decided to stop the work. Now he wants full refund for the money he pays for the material and the hrs I work for him cause I took time off from work to help him. Can I win this case?