Which son is most like Willy, and why?
In Arthur Miller's play Death of a Salesman we find that Willy Loman's two sons, Happy and Biff, are two men who act as if they still have not become adults. They are immature and socially co-dependent on their parents, and each other.
Happy, the younger son, is (like his name implies) a "happy-go-lucky" guy who is also a womanizer, mildly successful at what he does, and full of empty dreams. He simply does and says whatever people want in order to make them feel good. He does not have a clear direction in life. In the end, he is the one who intends to perpetuate Willy Loman's dream.
Biff, the elder son is Willy's closest approximation to Willy's dreams, yet not to Willy. Biff simply does everything Willy asks him to do. Like Happy, his only hope is for his father to be pleased with him. He achieves that much. However, he is also the one to discover that Willy's dream is wrong from the very beginning, and he is the one who wants to tell Willy about it. In the end, Biff breaks with the vicious cycle of lies and pretension that Willy has put his family through for decades. Biff wants to find out who he really is. He refuses to be like Willy.
Therefore, it is arguable that Happy is more like Willy than Biff. The reason is that both men have allowed themselves to live a life of fantasy without a solid ground. Both men are following someone else's dream. None of them wants to take a closer look at reality to do as they are supposed to.