There is another copy of the same video at YouTube without the tendentious headline. It seems authentic to me.

I couldn't find anything about it at his official campaign web site nor at his official Senate web site, nor could I find any comment about the video at Google News.

Despite the headline at YouTube, I'd say that's more likely his granddaughter than his daughter. The two kids say "and vote for my big daddy". Does "big daddy" mean "grandpa"?

Rather than a "caress" I'd call it a hug.

The girl looks to be about 10 years old. Does she even HAVE boobs? If not, why should we care that he puts his hand on her chest? Would we care if it was a boy on his lap? Is there any evidence he is treating her any differently than he would treat a boy of the same age?

The girl looks happy and comfortable on her grandpa's lap, being hugged by him. I don't think she would be happy and comfortable if he made a habit of groping her in an inappropriate way.

I don't see any evidence that this hug was anything but totally innocent.

I don't know anything about the Iranian man. Certainly double standards are odious, but I'd have to see what the Iranian man did, to know if a double standard were at work here.