According to this he qualifies for all majors plus TPC, but not WGC Bridgestone.
https://www.pgatour.com/fantasy/major-qualifiers.html
Aside from marketing reasons, he qualifies for the other majors ironically because he won TPC in last 5 years (2013) on course he hates.
As World golf ranking, he is currently 102. And the ranking is an avg divided by # of events. In Tiger's case it's last 40 events.
Could his OWGR go up? Sure. Not sure he's a slam dunk to be top 50.
That said, he has shown glimpses that I'm sure that the powers that be in non-Masters majors will provide exemptions for him through 2019 at least (if he doesn't win or Top 5 finish or otherwise check boxes)
ETA PGA tour priority
https://www.pgatour.com/news/2018/2017-2018-pga-tour-priority-ranking.html