I don't get it, why do they want to sink it in the Ocean? They could just leave it at the shore and make a touristic attraction of it, or use it for studies.
Right at the top is says "The old aircraft carrier, once the navy’s flagship, is packed with asbestos. No country, including Brazil, will let it dock to be dismantled." and later “deteriorating hull buoyancy conditions and the inevitability of spontaneous/uncontrolled sinking.”
No one wants that kind of liability, nor would it be suited for any use.
And what makes them sure that asbestos is not going to cause damage to the flora/fauna in the ocean?