I am truly deeply sorrow for the loss of your father, grandfather and beloved relative. Having lost my father recently, there are truly no words to describe the pain, despair and grief.
What is really helping me now to cope is drawing close to God in heartfelt prayer, and welcoming loving support and comfort from others. This certainly will not take away all of the pain, but it can cushion it. One of my favorite texts is at 1 Peter 5:10 (later half), which assures us, "He will make you firm, he will make you strong, he will firmly ground you." That is exactly what has happen to me and I hope the same for you.