The photo is from May of 1971 which coincides with this:
"In 1971, Colombo aligned the League with Rabbi and political activist Meir Kahane's Jewish Defense League (JDL), claiming that both groups were being harassed by the federal government.[9] At one point, Colombo posted bail for 11 jailed JDL members."
The young person in the back is thin and does look like Chaim. Chaim would have been 14 and a half then. The person looks like he has some stubble on his face and thus is about 16 or 17 or 18. It could just be a shadow though.