"Fg..i don't exactly have a money tree in the back yard, but could help some...with chemicals, etc...what do you mean by i will get the pool straight. and you get it straight..everything, you lost me there?"
You have to decide where you can help.. whether it is split the cost.. take all the cost on you.. whatever. Then you have to let him know what you can do.
Relax Eat Think Act normal React.. Smartly. Do something different. Emulate. Do Work.