Sorry to hear about your father-in-law's condition. I can relate to your situation to my dad's wherein he was all done in about 6 months since first major symptoms appeared and within 3 months of MDS diagnosis.
Neil Cuadra has summarized the landscape of MDS. I will just add my inputs on top of his.
Since there is problem in all blood cells, the situation may quickly take a downward trajectory. Transfusion is just supportive care. After some time, the body starts treating the transfused blood as a foreign body and starts developing defense mechanism against it, so it would end up being difficult to find a donor's blood sample which would become acceptable for transfusion even if the blood group is the same.
One other thing to keep in mind is what cytogenetic / chromosome abnormalities he has which manifest in the diagnosis of MDS. Some abnormalities are benign but some are severe. The progression of the disease to AML and the end of life often depends on the severity of chromosome abnormalites.
If you want to understand the severity of his condition, you can evaluate his IPSS (International Prognostic Scoring System) score (
http://www.qxmd.com/calculate-online...prognosis-ipss).
Some patients respond to active treatments such as Decitabine and Vidaza and some do not.
If it is really an end-of-life scenario, the best you can do is to provide maximum support and comfort to the patient and the people surrounding him - it is a very noble thing to provide "quality of life" to a patient who is approaching end-of-life. You can read about "end of life care", "palliative care" etc. in wikpedia or elsewhere to understand the concept.