Hello, I am a psychiatrist.
To answer your question, she might very well have depression, although it is unclear how similar to postpartum depression
it would be: Postpartum depression may take several days to occur, while depression due to a miscarriage would likely start pretty much right at the time of the miscarriage. Both can be severe, though, and their actual symptoms could be similar.
If she were to be placed on an antidepressant medication, most likely it would have been a TCA (tricyclic antidepressant; named for its molecular structure), such as Elavil/amitriptyline, Pamelor/nortriptyline, Sinequan/doxepin, Norpramin/desipramine, etc.
A trivia bit is that the name "Sinequan" comes from the Latin phrase "sine qua non,", meaning an "essential part," or a "an indispensable part."