What is this "if?" What is it that Marco has told me so many times?

[He watches him worriedly.]

I cannot fight wars, or be so strong to travel and help Marco, but I would like to believe I will be there for him in any way that I can. Perhaps subtly... [He leans closer and sort of nuzzles by his ear.] You will not lose your family. Please be sure not to lose yourself. Marco can do this.