This sounds like https://lightbot.com/. This app really helped my son think through problem solving sequentially before moving on to Scratch https://scratch.mit.edu/.

Since Op's brother is an adult he may be better served with a Raspberry Pi, which is not quite as "cutesy", but can still be interfaced with a drag and drop programming language like Scratch. Then one can graduate to more advanced projects. Check out https://projects.raspberrypi.org/en for inspiration.