Why 4yo still need milk? My daugther started with breast milk until 1, then formula milk until 3yo, slowly phase out. My son now 1yo 6 months on oat milk, now phasing out. Only before night sleep time as "supper". The kids already have their proper meals.

I see. I think it is not a problem. But look out for lactose intolerance. Not every can take the cow's milk.