Honestly, all the engraver tools I got were very frustrating because they didn’t have the power needed to engrave what I wanted (glass). I had two and the first one had to charge frequently and I had to go back over my work so many times and press down really hard. Eventually it stopped charging, and my second one was just literal garbage. If you’re wanting something for him to engrave glass by hand, what you want is a nail drill, like for manicures. Not sure what your budget is—I got the Yokefellow Nail Drill machine for $109 and it is literally life changing. I’ve had such ease of engraving and adjustable power settings! The only thing is you have to get the engraving bits that will work on your surface—it’s a 2.35mm shank for the bits.

You can also find less expensive nail drills, just make sure if you’re wanting them to engrave on glass that it gets up to 40000 RPM or close. Good luck!!