What Causes Restless Legs And Sleeplessness After Stent Operation?

Hello. My very healthy, active 88 yr old mom (90 lbs) went into hospital for heart stent. Went well. Night before release she said she had restless legs and couldnt sleep. 4 ml of morphine was given to her. She slept 4 days. Woke uo w inability to hold up head, swallow water, and no coordination. Was discharged to rehab ctr and took light case of pneumonia. Good days, off days after 3 weeks. Can now walk w walker and feed herself. What is general prognosis for a healthy elderly person who was driving etc before this? Thank you.