TBH I have never encountered Cranberry wine.
I would imagine, as with any fruit, the addition of yeast to the juice would start some sort of fermentation leading to alcohol but personally I suspect BM is pulling your leg ~ after all he is capable of drinking hospital hand wash if he knows it has alcohol in it

Juicing cranberries is no different to juicing any other fruit. Apply pressure to ripe fruit and juice will emerge ~ more pressure = more juice.
I reckon Nick's helpful link to recipes is your best bet. Cooking the berries is without doubt the usual option. The reason the supermarkets sell them is for the foodies who want cranberry sauce but think its better if they make it from first principles rather than buy it ready made in a jar. We buy ours in a jar as life is just a tad too short to fvck about making cranberry sauce or jelly starting with berries.