"We bring him a bottle of wine."
Translation:Gli portiamo una bottiglia di vino.
I am having difficulty understanding why only "Gli" is acceptable here and not "lo"
"Lo" is not acceptable here because it is a direct pronoun that answers the questions "Chi? che cosa?" (whom? what?)" , while "gli" is an indirect pronoun that answers the questions "A chi? A che cosa?" (to whom? to what?)"
- Lo = him
- gli = a lui = to him
for more explanations and examples check http://www.cyberitalian.com/en/html/gra_prpr.html
"Noi portiamo a lui una bottiglia di vino" This is a nother correct form, right?