If he has enough money to pay for his education, I would prefer him to study at UH Main coz there are lots of companies coming every semester looking for intern or  Co-Ops . I do not have much idea about UHCL. I am graduating from UH Main next year and I already got the job (Co-Op) in the company. Although, you pay big amont compare to UHCL and UH- Downtown, it is worth studying at UH - Main. 
And, there is only one way to get transfer scholarships at UH-Main campus. Its through Phi- Theta- Kappa Honor Society. You need to be the member of this organization and you will be qualify to receive the transfer scholarships.