whatever the choice is, the options will surely be based on his current situation which arised from his previous life decisions. No need to judge. Just be factual. Everything will be seen clearer than mineral water.
Nah in most cultures means "No". In my culture, it means an assuring "Here, take it from me". Only family and close friends use it with each other. With a change of tone, it could also mean a dismissive "That that, sucker!" to a rude person.