I lost my mother when I was 26 and she was only 52. She had been battling cancer on and off for six years... so we knew her death was coming. Didn't make it any easier.
The only advice I have to give - is enjoy every moment - even the things they do that annoy you now. Because you will treasure those memories the most once they are gone.
Great works are performed, not by strength, but by perseverance.