Not sure this is actual stained glass as most of us grew up with. Where the person uses pieces of cut or broken colored glass to make a picture. This stuff appears to be a large piece of glass that has been painted or 'stained' with something on the ...
There's no reason why you couldn't paint over the existing glass with glass paint if it is authentic stained glass, but keep in mind you could be destroying the value of the piece. Get permission first - original stained glass can be very expensive. ...
Based on the fact that I don't know what part of the world you live in, I would just advise that she take a course, many community colleges and night schools offer them. There are many safety concerns with stained glass (toxic lead, glass shards, and...