what brand is the webcam?

I think your friend might mean the driver for the webcam, not the video chat software. Then you need to provide the specific brand and model of your webcam so that I can google for you, or you can just download and install it from the official website of the webcam company.

I don't think you need certain software for video chatting, as long as you use the same one as your mom. Most of the IM softwares have video chatting function built in, you just need to configure it. Well, it will be configured automatically in most of the cases.