Something similar happened near my home town. A couple who kept to a strict raw vegan diet decided that even human breast milk was inappropriate for their infant. They also apparently felt formula of any kind was too processed and unnatural. They used to come to a deli where a friend worked to buy soy and almond milk. The kid was visibly malnourished and several of the locals got kind of concerned and started talking about calling social services. They disappeared from the area after a bit and I never found out how it worked out.
