I think there would be ways to transfer over to some streaming with relatively simple button pressing.

However, are there particular shows or channels that he must have or is it just any form of reasonable content is enough. I think you might need to take a look at potential content providers first and go from there.

If there are specific content requirements you might need two or more streaming services and that could get complicated.

Could he use a smart phone/device? Chromecasting might be the easiest way to put streaming content onto a TV. It's not fool proof though. It's also fairly cheap to try if you have a spare phone lying around. Would allow free content like Youtube as a starting point however finding the right show to watch might be too complicated compared to channel up, up, up until he finds something he likes.