If he's arming himself, then I'm sure he's planning something that he expects to prompt a US response.
He is just using the same tactic Castro has been using for the past 45 years to entertain his own people and make them forget about their own hardships. Now he is using the same fear of "US invasion" as Castro has used for the past 45 years. I was expecting this for a long time since he is such a Castro butt kisser.