You don't say how old your youngest son is.  However, maybe he needs to spend a couple of years off the farm, to get a bigger view of the world.   It just seems to me that tying him down with a farm that may not be large enough to be profitable may not be in his best interests.   If he wants to farm, he may need to find a niche market, something that not everyone else is doing.  It seems like milk today is a commodity, and you really need to have some volume if you are going to just market a commodity.   That's where a value-added niche market needs to be considered on a small farm.