People who exercise violent force against children for no apparent reason need to be locked (or strung) up. I'm not big on the 'benefit to society' angle, I'm fine with punishment as its own reward... but if you want to go that route, then the benefit is that while in prison he would definitely not be attacking more children.
As for his family -- if he acts like that in a public place, where he's known, and knows he's on camera, imagine how he treats his family in the privacy of their home.
"Our Country won't go on forever, if we stay soft as we are now. There won't be any AMERICA because some foreign soldiery will invade us and take our women and breed a hardier race!"
LT. GEN. LEWIS "CHESTY" PULLER, USMC