terminal stage in crohn's brain functions affected. coma.

my mom has had a severe attack of chrohn's. she has been admitted in the hopsital for around a month now.. and hasn't been able to take food in any form since then. after the chrohn's was diagnosed, she was put on steroids for recovery. but instead of recovering, her health remained steady for a few days, but since last four days, it has deteriorated rapidly. she is ventilator since last 3 days because her heart functions were affected. now her kidneys have   stopped functioning and she has been put on dialysis machine three times. the doctors say that there is no positive result from dialysis. before she was put on ventilator, she was given sedatives but now doctors say that she is in coma. the chances of survival are said to be much more if she takes food, but she was not able to eat or even drink anything  due to severe nausea and stomach aches then and now shes unconscious. shes on medical packs by food pipe inserted directly in her stomach but, doctors say that is not enough nutrition and she has to be given food to recover. what has to be done?