Hi Sal...you're poor little one.
Nan 1HA gold is supposed to be easier to digest....how long has he been on the karicare for? Usually bubs with lactose intolerance have frothy poo...not sure if constipation is also an indicator.
boiled water - cooled with some brown sugar may work as the sugar brings water to the bowel.

My bubs has always had probs pooing although she is on the Nan (however not hard poos - she just didn't go) we add an extra 10mls of water to each bottle, she wouldn't have the water by itself...so we are on senokot daily and trying to cut down now she is starting on solids. With the senokot I melt it in boiled water and then give it to her (just like a chocolate drink) and its natural, however it was her peadiatrician who advised this.

If I were you I'd talk to your MCHN also.