Yeah, he did, his folding bike, and sharing bike apps, like those that some cities have that you can use a phone app and pay to ride a bike for a specific time period you pay for. So, his problem is on multiple bikes.

While this all could be balancing problem when he tries to look around, if he tries to resolve that issue and it doesn't work, and all the other methods listed won't work either, it could be an inner ear problem for which he will have to see a doctor specializing in that sort of thing.