I am so sorry for your father.
Your father should be hospitalized. It seems to be an acute bleeding for example urinary tract bleeding or blood loss due to blood tests. The oxygenation of the tissues and normovolemia should be obtained by giving Oxygen and fluid (Saline, dextrose, Ringer solution, HES). He will benefit from the transfusion alternatives, such as iv iron, EPO, vitamins, stopping bleeding, adequate and balanced nutrition etc. For further reading you can look at the website.