Consider the following premises. For all x, x will not sleep. If Joseph were a server, then David is sleeping. Can we infer the following from them? Joseph is a server.
 From the fact that for all x, x will not sleep we can infer that David is not sleeping. Finally, from the fact that if Joseph were a server, then David is sleeping, and that David is not sleeping we can infer that Joseph is not a server, which contradicts that Joseph is a server. Therefore, the answer is no.