Before filing labor certification, there is another step prevailing wage determination and advertising and recruitment (this is not required for some academic position). This process is taking about 2-4 months. Then file labor which takes about 3-6 months. Labor may take more if it gets an audit. Once labor is approved, you can file concurrently I140, I485, EAD and advanced parole if the visa is current. Because of pandemic, visa has been current for each month for countries like Nepal, that is a nice part of the equation. You wont be out of status once you file I485 even if f1 expires. So if he starts now, it is likely labor to be approved within a year. Good luck. This is just a suggestion and not a legal advice.