Under a single person? Absolutely not. Philip II caused the country to go bankrupt
at least four times; and that’s
just Spain. It wasn’t very sustainable in the long run; too many outside threats (especially from France, the Ottomans, and England if it still goes Protestant) in addition to economic issues that would make it hard to sustain, inflation being chief among them. Charles himself found the empire difficult to run, but he did his best with the systems he had in place. Add that with how incompetent Philip’s successors were (and Philip himself in some areas) and the empire would certainly crumble before the century is out.
@Art Vandelay is right that a better move would be to give Burgundy to Ferdinand and his descendants. Or, have one of Charles’s other legitimate sons survive and give the Burgundian inheritance to him. Aside from Philip he had two short-lived sons, Fernando (born 1529, died aged eight months) and Juan (born 1537, died aged five months) as well as two stillborn sons (one in 1534 and one in 1539). All of them would be of age by the time Charles abdicates in 1555/1556 and could begin ruling in the Netherlands immediately.