It's difficult when you want to be responsible for everything but find yourself reliant on someone who isn't dependable, isn't it?
How big is Mojo? Is he small enough to stay in an ex-pen while you're gone? You could put plastic (like a plastic shower curtain) under the pen and put a bed, water, food, and toys in the pen with him. You could place pads at the other end. I don't know what other answer there is for you. But I certainly understand your problem and empathize with you.