This book is by Berkeley Breathed. Yes, that Berkeley Breathed who wrote Opus and Bloom County. Seems he is now writing children's books.
As you would expect both the art and the story are amazing. The premise is that Martians don't have mothers and after watching earth realize they could use some. Thus they come to earth and snag one, who as it turns out, isn't all that appreciated by her son. Sounds pretty win-win, but of course, things are never quite that simple.