I know not for everyone but my kids are actually more active in the house then they are outside. My house sort of goes around in a circle from room to room and they push large trucks around and around and around. We do bowling, roll balls, parachute etc all in the house. Outside they head straight to the sandbox. You might actually find they play more active if you have less stuff actually on the driveway and instead use it for games such as bowling, obstacle races, hockey or soccer with a net. It will get dry enough that they dirt area might be useable at least for some running. Is it possible that more of the kids could actually walk during the walk instead of ride. Has she ever considered that he is cranky because he has had outside time and now is getting overtired more easily. It hasn't been that long that we have actually been able to play outside because of the rain so they kids are kind of out of practice.