What does he mean by "vhf license"?

You need a radiotelephone operators certificate (probably has a new name these days) to use vhf for anything other than emergency but that is not tied to a vessel.

An actual vhf unit on a recreational vessel has no 'license' or registration, anyone can go and buy one at burnsco right now and use it without signing up for anything.

You can get an offical call sign registered (e.g. ZME3987) but it's easy enough to change the name of the vessel attached to it.

You can buy a register on the official part b ships register but it's usually only if you are planning on heading overseas on your vessel that you would need to do that.