Mothers do what fathers do: love their children unconditionally and raise them to be independent, happy contributing members of society. My husband and I have different approaches towards the kids, but those are much more based on personality and background than gender. We both love our kids to death and show them that every day, and we both try to teach them how to live in the world and help those around them in our own way.
It sounds like the reading you've done is focused on traditional gender-based roles of parenting, but as I'm sure you know, every family is different. My parents were kinda reversed; my mom was the disciplinarian, while my dad was the cuddler. They're still that way with their grandchildren today. So it's not a gender thing, or even a two-parent thing: it's a personality thing, I believe.
Your son may end up with a unique upbringing, but he knows that even if Mom can't communicate like she'd like to, she loves him. And he knows you love him, and that Mom and Dad love each other. That is the basis for a secure childhood, IMHO.
Since your wife can't really communicate her feelings about child-rearing, try to do things from time to time as you believe she would have, especially if it might be counter to how you'd do things. If you might be tempted to cuddle him when he gets a bump on his knee, while she might distract him by making him giggle, try that. It'll give you a different perspective on rearing him while hopefully letting your wife know that her perspective and priorities as a parent are still vital to the family as a whole.