Crazy question here, but...

My stepdad-in-law and mother in law came up for my son's 7th birthday. The day they got here, he was admitted to the hospital with chest pains and had it narrowed down to congestive heart failure. He' wanting to go home to Orlando, and Southwest has a nonstop on what is usually a 737-300, filed at 310 (at least for the last few days according to FlightAware).

Crazy question here, but I need someone to tell me what cabin altitude usually is 310 in a 737-300 so I can report this back to his cardiologist and see if they'll let him fly home. Otherwise it's a 12 hour rental car for the same money. Feel free to PM if you feel this is something that doesn't need to be out in public.

Thanks in advance!