Mother went in coma this morning. Possible heart problem. Please advise?

Can anyone give me a roundabout idea of what happened to my mother-in-law? She went to sleep last night and was found to be completely unresponsive this morning. She has sever scoliosis, high blood pressure and COPD (takes oxygen) and smokes a pack of cigs a day, age is 61 years old. Her BP was almost gone, as well as her pulse. She is now stabilized in the ICU, but she is in a coma. Her BP and pulse are normal now, and she is on a respirator to breath for her. The only movements she makes is slight eye blinks, and moves her finger a tiny bit. Her enzyme levels are very high which suggest a heart issue, but they can't tell us anything else. They dont know why she isn't waking up. Does anyone have a theory on what happened and what's to come? Since her vital signs are normal now, shouldn't she be communicative? Was her brain deprived of oxygen perhaps?