The failure at Nottingham really hurt his cause of getting a direct entry into the AO.

I think that a ranking of 100 will be enough. For that, he needs to get his present total of 379 up to around 410.
Bratislava 100K+H.He defends 5 points. A quarters appearence means a gain of 14 points.
Dnepropetrovsk 125K+H.He defends 5 points. A quarters appearence means a gain of 16 points.
Shrewsbury 25K+H.He defends 50 points. Although there will be a few withdrawals, he may not be one of the top four seeds.
Alex does not play in the Maui 50K+H during the last week of the Challenger calendar.He defends 5 points during this week.
So even if he reaches the quarters of both Bratislava and Dnepropetrovsk and wins in Shrewsbury, his total will be 408.
However, there is hope - this year, 11 players withdrew and as many as 13 players withdrew last year. And you never know, Boggo can win one of the two big money Challengers and make things really simple.

But I hope that he will change his decision and play in Maui. The field should be really weak and he will have a good chance of even winning the title.