Bottle the boy on Lamlac, don't know how much pygmy kids need per day though - someone else does probably.
But you have a problem in that to get the boy onto the bottle you have to separate him from mum entirely, maybe in a wee pen next to her? Once he is on the bottle 4 feeds per day are enough, my kids get fed at 7am, 11am, 4pm and 10pm for example.
Also you probably need to castrate the male kid asap, rubber bands are only legal in the first week. However you may find (if you are not experienced with lambs etc) to get the vet to castrate him surgically a bit later - speak to your vet about it.