If s/he can get new I-20 issued before April 10 he will be OK till July 10 (3 months but classes do not start till August ) the best option would be to join KAPLAN for GRE. The course is 3 months and can be extended for 3 more months (this u have to convince them u will do better and not satisfied by the score/progress). Good thing about GRE is you do not have course load as in college and can work outside.