and she wanted her kids to as well.m >> one time mom and i went, just the two of us. i hadn't been horseback riding in a while. and so i told her i didn't want to go more than maybe five, six miles. and she goes, "okay, well, i found this trail. it's eight miles, but you can do it." and by the time it ended, it was 16 miles. >> reporter: so she tricked you. >> yeah, but we had such a wonderful time. but the next day i was not moving.xt >> reporter: as for fred, he owned a multimillion-dollar company importing steel for construction. still, their dad wasn't all business all the time. >> in the traditional motherly roles, he would definitely step up and wasn't afraid to be mr. mom. >> reporter: the mueller kids say their parents fit one another perfectly.r >> he'd make a point of every night to try to do something nice for her. >> he was so proud of her, too. >> they'd talk all the time. anytime that there was any type of disagreement about, you know, who -- the dishes weren't done or some "honey do" chore kind of a thing, they would talk about it until they were completely