I suspect that in this particular polygamous family an elderly wife would be kicked out, but never mind my suspicions. I don't know what you mean by "unhealthy", it's obviously better for them than being on their own, which matches up with my definition of "healthy". Given that, if my daughter wanted to became one of these wives I would also be unhappy. And probably ashamed.
Because he claimed not to know the name of one of his wives. That tells me he doesn't care about them all that much. And if he doesn't, and they loose their attractiveness and their income generating abilities (the single mother subsidy only lasts for a few years, right? once the children grow up it's gone), I just see no motivation for him to keep them around.