There’s a lot of questions online about “can I do this or that without coding?”
Truth is, you have to know how to “program”, regardless of what you want to create. Being able to “write code” (via C++) is one thing, being able to program is another. You can build your app in UE4 without knowing how to write C++, but you will still need to know how to program via Blueprints, which is a visual scripting language. To get something to work, you have to program logic into the game.
For your game, you want to be able to use VR to sit in a wheelchair, ride around a space (i.e. maybe a house?), and probably interact with “stuff” (i.e. able to open doors, pickup things, etc.)
You need to be able to program all that logic with Blueprints. How does the wheelchair work? What button or control do you use to move the wheelchair? How does it turn? How do you interact with doors? Objects? When the game begins, is there a main menu? Is there a menu that pops up when you pause the game? If so, what’s in the menu? How’s it work?
You answer all of these questions by designing systems that work together; this is called game logic. You are literally (and painstakingly) telling the game engine how your entire world works, from beginning to end. The ability to program, is the ability to write all of this logic. Normally, a programmer will do this via C++, but with Blueprints, you can “write” all the logic via Blueprints, instead of C++.
So you see, you still have to know how to program a game/logic in order to create your app. Hope that makes sense.