Using a suppliers marketing video to boost sales

I have seen on facebook a dropshipper has edited a video he took from his suppliers product page and ran facebook ads and instagram ads with it. Is it likely the supplier would try claim copyright? What problems would he get running an ad like that?

A copyright complaint directly to Facebook or to him himself could be a problem, but we can not see the future so no one can tell you the answer with certainty. Maybe the supplier gave him permission to use it, if not, no one can tell you one way or another if they will go after him for copyright or not. Not everyone is aware if their content is stolen and some people even if they are made aware of it don't care.

Your best bet is to go to the content owner and ask them directly if you're worried about copyright related repercussions.

It depends if they have consent from their supplier.

Also, if the video is not "altered" as to indicate another product or company, and still promotes the supplier's product, why raise a copyright complaint? This is free advertising.