As for the medical issues, the main concern is that her credit will be impacted and the necessary score may not be there. If the medical issues are behind her or reasonably addressed and she can show a history of regular timely payments again, it shouldn't be an issue. Underwriters will all look at this differently so you could run into an underwriter who may accept six months of timely payments after the most recent credit issue (depending how severe the credit hits were) or you may run into one that wants a year. It also depends what happened immediately post-bankruptcy as well. This answer is unfortunately largely subjective so you'll get a different take from different underwriters at different companies. The only way to get a better idea is to have a mortgage professional review your credit profile and make sure they're someone who's very good with underwriting guidelines (otherwise you may end up chasing your tail) to give you some feedback.
Bottom line, a year from when the credit issues were resolved is a pretty safe bet if you're not in a rush but my disclaimer is that none of us reading this know what her credit looks like so we can only make high level responses.
You'll want to keep in contact with a loan officer you trust who keeps current on guidelines if you're in one of these situations. I.E. 0 seasoning after a short sale for FHA loans if it was paid on time the previous twelve months and wasn't previously a FHA mortgage.