My boyfriend has primary cutis verticus gyrata that has progressing rapidly, there seems to be very little research on this dessease why is that?

A lot we don't know: Cutis Vertica Gyrata may not get much press but it is being investigated. Here is a good review: https://emedicine.medscape.com/article/1113735-overview#a5. For example, there have been 5 studies on its genetics and 68 articles mentioned in this review. Uncommon (1 in 100,000) conditions which don't lead to massive morbidity or mortality often don't get funding.