Please my dog maltese half poodle I fed him junk food his very weak won't eat even drink when he sees food he gets excited please answer me his still a puppy 5months help his very thin I.. :( please

What junk food did you/do you feed him? What type of dog food does he eat normally?

Dogs dehydrate and die very, very quickly - and painfully. If he is weak he needs to see a Veterinarian.

This could be anything. Has he had his parvo shot(s)?