Talk to General Physician on Heart Or Respiratory Illness

hii there.few days ago my brother in europe was diagnosed with severe shortage of oxygen in blood.he says one day he felt severe pain in chest which went away after few minutes but after that pain he felt shortage of oxygen.his oxygen level is 30 percent in blood.he also has high cholesterol and a diabetic patient type 2 diabetes.he is also complaining of severe night sweats for almost six months and his ecg report is also abnormal.he says he felt pain in centre of chest currently that sometimes go to back and sometimes to shoulder.could anyone predict whether it is a pulmonary disease or a heart issue.his spirometry report would take time am very anxious about him.kindly help me