Is there no national body that could sponsor him ? I think that the government sponsor many good athletes in many countries.
If he could mangage to get some good results in some important competitions, it would probably be easier to get a sponsor.
A few tips:
Travelling expenses could be cut, order cheap tickets far in advance. Live in cheap motels.
Buy food in larger batches, were it is cheapest.
Is it needed to rent a car, what about public transport.
Does he need a car in his home country ? Could he sell it and use the bus?
I would also suggest to visit all the local companies and ask them to sponsor him.