He married her a long time before he converted. Like five or six years before I think
Yes, sadly, if one spouse converts, you just have to wait for the other one to receive the grace of conversion (or cease resisting it if they do receive it and don't respond).
There is such a thing as the Petrine and Pauline privilege (not sure which one would apply here), but if he wanted to stay with his wife (with whom he has a natural marriage, neither JD nor Usha, AFAIK, were baptized when they married), then he probably wouldn't want to invoke it. Both privileges may be invoked, but do not
have to be.
In a place such as eastern Kentucky, where JD is from (or rather his family, he had ties to the region and evidently retained the religious mentality in his youth), it is very common for people, even if they have some notional attachment to Christianity, not to be baptized until later in life, or never to be baptized at all. They just don't understand its necessity for salvation (not looking to get into any BOD debates here). A lot of those towns, such as Middletown, Hamilton, Grove City, and so on, even though they are in Ohio, are
de facto Appalachian enclaves, many people from eastern Kentucky and West Virginia go there for employment, and maintain facets of their culture, including religious ones.