Why does Bud believe that living with three girls is better then living with an older boy in Bud, Not Buddy?
Bud says that living with three girls would be better than living with an older boy because the little girls would treat someone real good, while an older boy is only going to want to fight all the time.
Bud gives this advice to his friend Jerry Clark. Jerry is only six years old, and is very unhappy about being sent to a foster home from the orphanage. Although Bud isn't happy about being sent to a foster home either, he is older and more experienced with being shuttled around. Better able to handle things than little Jerry, Bud tries to make his friend feel better about a situation which neither of them can control.
Jerry is being sent to a home with three little girls, while Bud is being sent to one with a boy a couple of years older than him. Bud tells Jerry that it would be better to live with the three little girls because "they're going to treat (him) like some kind of special pet or something...the worst thing that's going to happen to (him) is that they're going ot make (him) paly house a lot". Bud's analysis of the situation really does make Jerry feel better; the younger boy cannot help but smile through his tears.
The reader never finds out how Jerry's placement turns out, but Bud's estimation about what would happen living with an older boy turns out to be quite accurate. Bud is sent to live with the Amos family, and Todd Amos does indeed beat him up and torment him incessantly (Chapter 1).