There's a few points worth discussing. I will talk about my own experience, maybe you can show him this and it'll be some help to know what being an indie dev is actually like.
I did my undergraduate degree in Games Design. Bad decision. It touched on the basics, but in the end I still couldn't make a game. A few years later I decided to learn how to use Game Maker Studio. I knew nothing of programming. By the end of the project I knew something, and had brought a game from concept to completion. I was smug. It sold almost nothing. I was sad.
Later I regained some confidence, and decided to do a postgrad conversion course for people who wanted to learn programming. I'd made a game, how hard could it be? Turns out... quite hard. Stuff like multithreading however is thankfully something I've never had to use outside of a classroom.
So I graduated, got a programming job for an IT company, have been at that job for two years. In that time I've also spent most of my spare time after work and at weekends doing games development. Progress is slow.
For someone who wants to make their own game, alone or in a small team, you have to be the person who can implement their own ideas. Small teams cannot afford a dedicated games designer writing design documents all day. Because most people can't afford to hire a team of programmers, they need to be programmers in order to be designers. I would go so far as saying it is preferable that you can code regardless. The crux is that if you want to make your game, and not somebody else's game, then you need to be able to do it yourself.
Making a game is hard. Very hard. If you want to make games, you have to be willing to come home tired from a 9-5 and force yourself to write some code for a God awful problem nobody you know can help with. You've been struggling for weeks, and feel like crying, because how is this ever going to be fixed? To feel sometimes like you don't know if this will ever end, and to wonder if you're wasting your life. To have genuine self doubt, and yet to conclude: No. This is the right decision. To have that bloody minded determination.
Spoiler alert: I fixed it. So your brother needs to get that. Maybe he can be your art department instead? There's nothing wrong with that, but it'll not be any less work to learn and make what you need. Whatever he does, he needs to be just as busy as you. You're an ideas guy? Yeah, get behind the ideas guy who can do art, or the ideas guy who can code.
With that pep talk concluded, give him something like Unity or Game Maker. Tell him to think of making a very simple game. One step at a time. There's plenty of learning material online for those two engines (and others), and something like TutorialsPoint will help introduce him to programming basics.
In my case, after struggling with GML and Game Maker Studio, I read the first hundred pages of Programming: Principles and Practice Using C++ by Bjarne Stroustrup, which was enough to start with Unity and C#. Just teaching him how to work on his own and solve problems on his own with the help of Google and StackOverflow is half the battle.
Show him how to use an IDE like VisualStudio, and the debugger, and hold his hand through basic C# (for example) tutorials. Be patient. Variables, functions, arrays, classes, etc. We programmers forget how scary it is to begin. I can't overstate how important it is for you to help him through those baby steps. Be patient. Not everyone is as mad as I to go it alone. But if you support him through the basics, and get him able to do simple debugging and creating simple classes, he'll start to think of creating games in programming terms. Then he'll get it.
You can't convince him to do programming. He just needs to decide if he really wants to make games. Then he will realise he has to become a programmer.
