I keep on trying to answer this, and struggling to find the words. If I were in your situation, I'd be angry as well: maybe not specifically at my dad, but just at the injustice of this happening when you need to be able to turn your focus inwards on yourself.
We have had family bereavements and major incidents around the time of birth for me, and the only advice I can give is to wait and see how you feel once baby is here. A newborn can be completely exhausting- or you may feel a million times better than you did late pregnancy. The stress may bring on labour early, or could mean you go overdue. The only certain things are that your dad is, at the minute, in the right place, the medical staff seem very clued up on things and at some point in the next month you're going to be holding a newborn in your arms.
Nobody expects you to do it all. At this point, your mother does have other support available to her- though obviously, not in your league
Take time for yourself to finish growing this baby and to enjoy and appreciate the miracle that is birth.