The actual risk of botulism poisoning from water bath canned low-acid foods (such as fluid milk) is fairly low. This tends to make it attractive to many who don't have a pressure canner or don't want to be bothered with using one.(posted 9632 days ago)That being said, while the risk is low the consequences of encountering botulism poisoning are severe. The actual number of botulinum related deaths have declined but this is largely because of the sophisticated medical technology we now have which allows months of intensive care and still more months of physical therapy.
If you want to boiling water bath low-acid foods such as milk it's your call but you should be aware of what it is you're doing. It seems to me you also have an ethical obligation to let anyone who might consume the milk know how it was processed since the natural assumption will be that it was safely preserved. A pressure canner is not that hard to come by or preserve the milk by making cheese out of it or turn it into meat by feeding it to the pigs. Even recommending pressure canning is more than most recognized canning authorities are will to commit to.
.......Alan.
The Prudent Food Storage FAQ, v3.5
http://www.providenceco-op.com