Cocus, Brya ebenus, also known as espino de sabana, granadillo, cocus wood, cocuswood, and coccuswood, is a species of flowering tree in the pea family, Fabaceae, that is native to the Caribbean islands of Cuba and Jamaica. Horticulturally it is known as the Jamaica rain tree. Average Dried Weight: 72 lbs/ft3 (1,160 kg/m3). Grain is usually straight or slightly wavy. Fine, even texture with good natural luster. Janka Hardness: 3,720 lbf (16,550 N)
Sheesham, Dalbergia sissoo, known commonly as North Indian rosewood, is a fast-growing, hardy deciduous rosewood tree native to the Indian Subcontinent and Southern Iran. D. Sissoo is a large, crooked tree with long, leathery leaves and whitish or pink flowers. Average Dried Weight: 48 lbs/ft3 (770 kg/m3) Sissoo generally has a straight grain, though it can be interlocked—sometimes severely so. Texture is medium to coarse with a good natural luster. Janka Hardness: 1,660 lbf (7,380 N)
I think, on the basis if the above, we can say there is no legitimate reason to call Sheesham cocuswood. Different continents (India vs the Caribbean), different families (peas vs rosewood), one slow-growing (to the point of near extinction), the other fast-growing. The technical benefits of cocuswood shine out - 1160KG/M3 compared to 770, fine even texture compared to medium-course, double the hardness figures.
Sheesham is a furniture timber (like teak, walnut, maple), not a wind instrument timber. I reckon wind instrument timbers start at the weight of water. Boxwood 0.98KG/M3
I just noticed Waddywood, an Australian acacia from the Simpson Desert, clocks in at a staggering 1430KG/M3. That makes it heavier than Delrin (Polyoxymethylene)! Janka Hardness: 4,630 lbf (20,600 N). No wonder it’s called Waddywood (a waddi is the indigenous name for a club). Looks gorgeous too! I want some! (Alas it is rated “rare and protected”.)