It's an Arabic proverb , i'll try to express it in English : Literally,
If you called an alive person , he's supposed to answer . But no life in what you calling.
Well, i guess it means that there's no use from trying to advise a person or asking him to do something because only alive people can answer you but he's not.
note: " he's not" doesn't mean he 's dead . but mean he will never answer or listen to you as dead people.
Simply, we use " لا حياة لمن تنادي" as an idiom to refer a person who never listen to you ,as i mentioned before or a stubborn person who insist on his own opinion.
Hope it helped , and please ask if not clear ;)