Calculator is at
http://www.jamorfold.com/icm.html if anyone else was confused (like htf can you need more than 50% pre?!)
Let me know if this is bad, but this is how I think he thinks (as an unknown):
1: His hand can't face a 4 bet because he perceives your 4 bet range to be relatively tight as an unknown. However, cos of the late position dynamic he thinks you could easily spazz and shove lighter some % and 3 bet folding feels a bit spewy and shoving is +EV so he should do that.
or
2: Because of #1, he will think you will perceive his range to be super wide, so you will call wider than you will 4 bet (seems unlikely) and so he ships with the nizzles.
or maybe some other thought process.
I think unknowns are more likely to be #1 and generally won't balance very often if at all. Since their shoving instead of 3 bet range is pretty narrow and at the bottom of what should probably be in their 3 betting (or at the top of their) range, I think AQ is probably good enough to call here.