But could he have made it to that island with the fuel he had on board?
Yes he could have but just barely and with luck.
They said he had fuel for 7.5 to 8 hours at 520mph — 3900 to 4160 miles.
The path that he flew would have been 4230 miles — out of reach but it could still have been a target destination and may be in the waters a couple hundred miles short of it — if that is the island on his computer.