And what a lucky thing for him! Interestingly, most children don't like milk unless it is chilled - so they can't detect what it really tastes like. Now, maybe the taste of it is tipping them off to the fact that they shouldn't be drinking it. Cow's milk is unhealthy. Especially for children (it has been shown to be linked to Type 1 Diabetes. For more information, check out The China Study by T. Colin Campbell, or just google something like "dairy heart disease," "dairy cancer," etc. There are links that say that dairy might help prevent diabetes, but I'd check out Campbell's book before deciding. He's one of the top nutrition scientists around the world, his research is extremely thorough, he draws from other, extensive studies - again, at the top levels of nutrition science - he documents everything copiously and he makes a compelling argument.
Not only is cow's milk bad in and of itself, but they had to increase the legally allowable limit of white blood cells (that's pus) because factory farmed dairy cows generally have mastitis. So lots of pus from the infection gets into the milk (check out John Robbins' Food Revolution for more on this). Also, you have bovine growth hormone to worry about, as well as high levels of pesticides that are bioaccumulated in the animal from years of eating pesticide-laden crops (including genetically engineered ones, like soy and corn, which are genetically engineered just about across the board, unless they're organic). Then there are dioxins. I don't know where those come from, but in my research I have found that butter, milk, meat/fish and eggs rank highest in dioxin concentrations. Best avoided!
It's crazy stuff like this that made me vegetarian. Try other things for him to drink, like rice milk, soy milk, hemp milk, watered-down juice, etc. Most importantly, of course, just plain old clean, filtered water. Since Americans are generally chronically dehydrated, as a rule, getting him into the habit of appreciating just water, in its own right, will be doing him a wonderful favor.
L.
PS and yes, soy is perfectly healthy for anyone, boy or girl, child or adult. It's a bean. It's no magic solution nor evil potion. If you're worried about hormonal effects, get rid of the plastic and chemicals in the house (/garage/etc.)!!