I am a professional CCTV installer and I would recommend against this.

Consumer grade home tech products are way too easy to hack (there are a few darknet diaries episodes about this but a quick Google will show you plenty of examples)

In the rare occasion that we install cameras indoors, we generally wire their video feed via the intruder alarm which means when the alarm is unset (i.e you’re at home) - the camera is off. Not just ‘not being watched’ but completely powered down and disconnected from everything.

I work in the industry and I wouldn’t have one inside.

It would be interesting to know why he wants one, there may be other solutions for him…