So here's the thing.
You were a great friend by helping him to get the job. As a friend, that's all you can do.
You bring him to the door, but he's the one that had to walk through it. He got the job. That's it. That's where your responsibility ends. From that point on, it was on him to save money and figure out how to get to work without you. What happens if you have a family emergency? What if you're sick? If you get Covid, is your friend going to be out of work for a week, also?
It will feel bad because you might think you're letting him down. But you're his friend. You're not his father.
He's going to have to find a ride, borrow a car, get a bicycle. Find another co-worker to take him.
It is what it is.
If I were you, what I would do is give him as much notice as possible. "Dude, you have 2-3 weeks or whatever because I have to take advantage of this opportunity. You undersand...etc"
