Friend on facebook just diagnosed with basilar artery migraine. In my country we never heard that term. Is that something new?

Well known. This was nicely described by bickerstaff many years ago. The basilar artery supplies the balance center, vision areas, and nausea areas as well as regions that can cause confusion and disorientation. When these areas are primarily involved in a migraine attack, we refer to it as a form of basilar artery migraine.
Not new. There are several types of migraine headache. This type is due to a "defect" in an artery at the base of the brain. Usually preceeded by a symptom such as dizziness, double vision, change in coordination, and other symptoms 10 to 15 minutes prior to the headache.
Basilar migraine. This is not a new diagnosis. This has been around for some time. It is a migraine that manifests as headache, double vision, slurred speech, vertigo, or trouble walking. Decreased blood flow to the brainstem and/or cerebellum may be associated with this type of migraine.