Hi, thanks for writing to HCM.Fractures
of the metatarsals are considered "Minor" fractures.
An aircast (pneumatic walking brace) is more versatile and works as an alternative to traditional cast especially for minor injuries around foot and ankle.
Yeah, definitely you can sleep with the aircast on.(Adjust the pressure in the air cells so as not to exert too much stiffness
or tightness on the limb)
The swelling will subside within 10 days (maximum) with the foot end kept in elevation most of the time and with regular movements of the toes.
Hope this helps