Complications associated with Prolonged bed rest

Jason has been on prolonged bed rest due to his surgery and injuries from the MVA. Discuss the possible complications associated with prolonged bed rest.
2.  What information would you provide to Jason and his family to prevent these complications?
3.  How would you ensure Jason is stable on his feet when he is able to begin mobilising? What member of the 4. 4.  MDT would assist you with this?
Reference required.