Jonas,
I second what has been said and written before; I will try to cheer you up saying that heart attacks are worse in younger people, because the heart is not yeat ready to cope with them. With the years, our heart develops systems to overcome problems with blood flow. This goes to say that -strange as it may seem- even in the case of an infarction the prognosis is better in older people, compared with -say- men in their forties.
Hope that both you and your father will have a Christmas "as usual", which seems to me the best thing to wish you right now.