Ex,
The best you can do is hold your wife's hand, take care of your little one, and live life. I watched my father linger in a coma for a month after brain surgery to repair an aneurism in his brain. the surgery worker, but the trauma to the brain caused a stroke. One of those rare complications that almost never happens, that Dad knew was a risk, but that he accepted as trade for removing the ticking bomb in his head. I wasn't ready to lose my Dad, right up until the point where I was alone with him in the room, and i said "Dad, if you have to go, go. We'll be alright." He died the next day. I like to think that I made it okay in his mind to let go.
not that it is a good time to ask, but does she have a will, a health care power of attorney, a "living will" and such prepared. Might want to consider these while you still can, although it's not going to be easy for you to suggest it. Makes you look like the Grim Reaper, but can be very helpful if needed. They were for us.
Best wishes, prayer, and such.
Chris