Toby, the chances of your son getting the job he wants in the Air Force are exactly what was written in his enlistment contract. That contract is on boilerplate. The Air Force will honor its contract and expect him to honor his contract. If he fails to honor the contract, he's in serious trouble but to date, the USAF has never once failed to make good as agreed.
That holds true of all the Armed Forces.
However, no one can be sure that your son will finish basic training the way Obama wants to rip the guts out of our military, starting with safety training so that he can get more "worthless whites" killed. He may face discharge before he gets to technical training.
The wild and irresponsible massive upheavals we will suffer, one right after the other, will first bankrupt our economy, shut down Social Security, cripple the VA, end all education programs for veterans. That is before we fall flat on our backs as a nation and suffer the ravages of war that Obama hopes to encourage -- by any means possible.
The ONE thing your son has going for him is that his contract antedates the horrific upheavals the Democrats will inflict against us to put us in another 1929-style depression.