Is this legal in Michigan?

I doubt it is legal, but that isn't the point.

Go back and try again with a different person. They may just wave her right on through.

If they refuse her again, ask for a supervisor. If they still refuse to give her a license, get very specific reasons in writing. There is undoubtedly an appeal process. Ask what it is, do your homework, and then file an appeal.

(For an appeal, you may need to get a written statement from her doctor stating she is physically able to drive and does not represent a danger to herself or other motorists. Something to that effect.)

It is a tough to dispute a refused driver's license, here is why:

The law regards driving as a social privilege and not a right. As such, the protections afforded to would-be drivers are much lower that would be afforded a constitutional right.

The DMV (in Michigan there is no DMV by the way - driver's licenses are issued by the Secretary of State) has wide discretion to deny driver's licenses if there is risk of jeopardizing public safety - even if the would-be driver doesn't have a history of causing harm.

For example, I've read several cases where potential drivers were denied driver's licenses because they suffered from epilleptic seizures - even though they've never had an accident behind the wheel. Driver's licenses are legally denied in such cases because the risk of jeopardizing safety is quite high.

Must we first wait until a severe automobile accident capable of threatening life or limb takes place before we can deny issuance of driver's licenses? I would hope not.

Well thats gay and stupid