Who is Athos from The Vicomte de Bragelonne and what is their importance?

Athos, The comte de la Fère is a former Musketeer and the father of Raoul, the Vicomte de Bragelonne. Athos has become old and an alcoholic. He used his power to help Charles regain the monarchy in England. Athos dies when he learns of Raoul's death.