Good to hear that the surgery went well.
I have family in Alpena and Presque Isle, and live in the Flint area. We also used to do some business up there, and I've made countless trips up in all conditions.
If she is going to meet family in Flint, then I would recommend taking US-23 up the east side of the state. I-75/US-23 run together as one freeway between Flint and Standish (roughly 65 miles north of Flint) and split off at exit 188. This route is well travelled, and while it's not a divided highway or expressway it is one of the better ways of getting to Alpena from the Flint area. There are decent amenities and stopping areas, and the road conditions on US23 will probably be better than taking M-32 across from Gaylord (the strong north winds and a few inches of fresh snow over the past couple of days have made the east/west roads pretty slick in places). That stretch of M-32, while nice country, can be a real drag. Likewise with M-65, which on the map might seem like a good route, it is sparsely populated and wouldn't be my first choice for my wife in the winter.
The former Holiday Inn, now Sanctuary Inn, as other have recommended is not a bad place to stay, although I have not been there since the name change. It's pretty much right next to the hospital and we used to have family events there. There's a Best Western on the west side of town that I have never been inside of, and a Day's Inn too I believe. Unfortunately I'm not familiar with any of the Mom and Pop hotels/motels since we usually stay with family.
Alpena isn't a huge town but there are plenty of services and assistance able to be rendered if your wife finds them necessary.
Our thoughts are with your family, and we hope to hear more positive news!
BD