How is Uncle Jake a positive influence on Marc in the novel, Marc’s Mission?

Jake is a former Navy SEAL who has a great deal of self-discipline, and he urges Marc to practice that same kind of discipline. Jake shows Marc how to overcome problems, usually by hard work and changes in attitude. Jake has ways of making Marc understand things, and he often sets Marc working on tasks specifically to show him why a particular method is going to work. Jake also has a way of showing Marc that he is happy or disappointed with any of Marc's decisions, and Jake's disappointment always makes Marc take another look at what he is doing.