What is the point of all the hardwork we put into our lives.. if one day we just go?

My uncle just ped away in the middle of a very busy time in his life, with his first daughter due to be born in 4 weeks and a busy time in his career. It was a shock to me and made me think.... what is the point to everything we do? All the hard work he put into his career, his relationships, his skills and knowlege... it is all worth nothing because he is gone, ceased to exist, just stopped being. I don't understand anything anymore and I've lost all motivation.