There were three sides: ISIS, the rebels and government/Assad forces. In the clip he’s referring to the rebels fighting ISIS. Listen to it again, it is very clear he’s talking about meeting and talking with the rebels, not ISIS.
He probably did meet ISIS also, but this clip does not prove that.
He’s not talking about meeting ISIS.
There were three sides: ISIS, the rebels and government/Assad forces. In the clip he’s referring to the rebels fighting ISIS. Listen to it again, it is very clear he’s talking about meeting and talking with the rebels, not ISIS.
He probably did meet ISIS also, but this clip does not prove that.
Look at the pictures on the internet and there are confirmed ISIS leaders he is with.