Unfortunately last week they found a tumor in my father's brain. Appearently it was quite big and it was on the right frontal lob which controls the personality. Neurologists say that this is why he was acting odd. Yesterday he had a brain surgery and he is still in intensive care.
Doctors told me that right now he is ok and they'll let him out of intensive care to a regular hospital room in a couple of hours. They said that they removed all of the tumor however it does look like a glioma which is not a really good thing. We will be sure how to treat the possible remains when the pathology results come in 3-4 days