In spite of all the comments on Falstaff, I think he is hugely misunderstood -- especially by followers of Professor Harold Bloom (Shakespeare: The Invention of the Human). Who is Falstaff?
1. He is an alcoholic. (Ask any health professional.) He does not carry a bottle or sack instead of his pistol onto the battlefield because he is "free" [Prof Bloom]. That bottle is more important to him than the battle.
2. What would Shakespeare (and his audience) have thought about a highwayman?
3. When given command of a troop of foot, he uses the appointment as a chance to swindle his employer. First, he impresses a troop of reluctant well-to-do and allows them to buy their way out, then he impresses a troop of starving beggars. He does nothing to equip them; even to clothe themselves they must steal laundry as they march. Then he deliberately leads them to pointless death on the battlefield, so he can keep their pay.
This is genuine evil. He is an ogre who fattens himself on the flesh and blood of the poor and destitute.
4. Who is his employer that he is defrauding? His friend and patron, Prince Hal! Prince Hal is engaged in a desperate fight, not only for his throne but for his liberty and life. (Pretenders to the throne tend to die when they fall into their enemies' hands.)
5. At the same time, he is desperate to retain Prince Hal's favor, and when he finally loses it, the shock of it kills him.
Evidently, Falstaff is not only dishonest, but he does not even understand the concept of honesty. He is, in the clinical sense of the term, a psychopath.