I thought you were supposed to be a fantasist, right? Isn't that basically the deal with you? You dream things up. Isn't that true?
The Old Man sounds the way one might imagine Sam Shepard's own father asking him about his career. As a playwright and actor, Shepard took a very different path than his Air Force retired, and later, farmer father. Shepard's artistic path might be perceived as unpractical by his father's generation. The Old Man expresses this sentiment to Eddie. Perhaps the Old Man has been far away from Eddie for some time and has heard through word of mouth or by letter or phone call what Eddie has been up to lately. The only indication of Eddie's occupation is when May calls him a stuntman. Whether or not Eddie is indeed a stuntman or if that is just a name May calls him to describe his risk taking and love for rodeo and ranch activities is not important.
The Old Man describes Eddie as a "fantasist" that applies to Eddie in the way he lives his life and views the world. Eddie has a hard time living in reality. He enjoys living in the moment like when he decided to drive thousands of miles because he missed May's neck, but he cannot live with the truth. He denies his affair with the Countess even when she shows up at May's motel room. Eddie does not let the fact that he and May are siblings bother him or stop him in his pursuit of her as his lover. He also perceives his actions in the past with a silver lining instead of the way May sees them—as reprehensible and hurtful. Eddie says that lies are not lies if you believe in them. His perception of his life is an illusion. He decides for himself what is moral, what is true, and what is possible. This idealism is somewhat charming in Eddie, but also prevents him from facing his reality which includes the feelings of others including May.