Hello ! your description of oxgen being low and CO2 high is medically termed type 2 respiratory failure. It can result from chronic lung diseases like COPD (Chronic Obstructive Pulmonary Disease), Bronchial Asthma, Interstitial Lung disease, Obstructive sleep apnea. But problems elsewhere in the body (apart from lung) in the breathing circuit can also cause type 2 failure, like intake of drugs that suppress the respiratory stimulus from brainstem , abnormalities of chest wall causing problem with ventilation. So kindly provide the exact diagnosis of your mother s condition so that prognosis can be commented upon .