I have been there and this is what I finally settled to.
If he starting from complete newbie (no programming background etc), I would suggest start by learning programming only in well controlled environment. Be it python, MIT scratch (for start) or even Basic. Together with this you can try simulated robotics with something like Roboacademy[1]. It is a simulated robot, that you program with very simple instructions to solve pretty amazing problems.
The reason I say is this. Robotics is at the juncture of programming, electronics and mechanics. Learning robotics from zero is learning all of these 3 simultaneously and in a frustrating way. It is frustrating because, real world stuff breaks/faulty parts, misaligned parts, buggy firmware etc. Suppose you want to give a simple instruction move forward 3 seconds, turn right, move forward 2 seconds, but real world stuff has misaligned wheels, it wont turn exactly 90 degrees, it varies between servors/motors of the same model/make, there is jitter etc etc. So many fine-tuning and adjustments you have to make in the real world, and that takes focus and interest away from the creative fun part.
So my suggestion would be learn programming, learn a bit of electronics with age appropriate kits etc, before combining them to robotics.
The reason I say is this. Robotics is at the juncture of programming, electronics and mechanics. Learning robotics from zero is learning all of these 3 simultaneously and in a frustrating way. It is frustrating because, real world stuff breaks/faulty parts, misaligned parts, buggy firmware etc. Suppose you want to give a simple instruction move forward 3 seconds, turn right, move forward 2 seconds, but real world stuff has misaligned wheels, it wont turn exactly 90 degrees, it varies between servors/motors of the same model/make, there is jitter etc etc. So many fine-tuning and adjustments you have to make in the real world, and that takes focus and interest away from the creative fun part.
So my suggestion would be learn programming, learn a bit of electronics with age appropriate kits etc, before combining them to robotics.
[1] https://www.robomindacademy.com