I would really think about what sort of position he would be able to get. My guess is that most start-ups are (especially at first) going to avoid hiring anyon

I would really think about what sort of position he would be able to get. My guess is that most start-ups are (especially at first) going to avoid hiring anyone that isn't essential to what they do. If you can't pinpoint value-adding skills that your brother brings, he may not have a good shot. When does he graduate? Really just need to do a cost/benefit analysis, but I might weigh finishing the degree heavier than you would... pays off in the next jobs as well, not just the first one.