Who is Milt Abrams from Earth Abides and what is their importance?

Milt is a former jewelry store owner who has survived in New York City. He is living with a woman named Ann who is clearly not his wife, and Milt seems somewhat embarrassed by the fact. Milt and Ann are living in a nice apartment having had the opportunity to take their pick of places. They play cards together and intend to remain in the city. Their fate is unknown.