It isn't likely to happen.
It's happened at least once. There was, a few years ago, a program
"TurboComm ViP" by Pacific CommWare, that was advertised as enabling use
of Winmodems in DOS windows under Win95. It might work under later
Windows versions. It was not freeware (advertised for $40), and I don't
know if it's still available--a quick Google search didn't turn up any
link that worked.
But an external modem is not needed to get one that a DOS program
can use. Any internal so-called "hardware" (controller-based) modem can
work under both DOS and Windows, and would probably perform better than a
Winmodem of the same nominal speed using a Windows serial port emulation
driver like TurboComm ViP. Sources of used computer accessories should
have plenty of cheap ISA hardware modems up to 56K available. If you have
no ISA slots, there are also a handful of PCI hardware modems, though they
are much harder to find. Since Linux users also have problems using
Winmodems, a Google search for something like "linux-compatible pci modem"
should yield information on models that would work for you.