Cows milk is not unsafe after 6 mths, but as a main drink it is considered to be lacking in iron, and unless a baby is getting iron from other sources, the thinking is that the baby might go short.
'Tis a judgement call as to whether a drink 3 x a day on weekdays constitutes a 'main drink' or not, and other factor would be how often the baby is being bf - if it's no more than once or twice then the cows milk would become more of a 'main drink' IYSWIM. If the baby is bf ad lib day and night, not so much.
Can't see the point of boiling the cows milk - does the HV think this might make it easier to digest or something?
Personally, if it was me, I'd give this baby the cows milk in a cup, unboiled, at the nursery, because if it was me the baby would be getting lots of bf, and I'd be making sure the baby got iron-containing solids, too. I'd not want to be faffing round with formula which needs more careful preparation, or bottles. But that would be my judgement - no hard and fast rules here!