Is Liam defending anything from last year for this?
Defending 8 points for reaching QR2 last year so these now defended and he will be on at least his current 557 ranking points in the post US Open 11/09 rankings.
Any further US Open qualifying and MD wins will be profit. He also has Challenger entries for the coming 2 weeks.
Purely from the US Open, he would need to qualify ( would then be on 584 points if he lost in MD R1 ) to have any chance of being top 100. Though he would probably need a MD R1 win as well ( would then be on 619 points ).
He has no further points due off until 02/10 so does also have a window for a few further weeks.