Always good to try help but above post is totally wrong. Its not a statistical anomaly, and his range (based on HUD stats) is 38% not 18% (38% is very wide for CO so you should be able to 3bet bluff him a lot and get many folds). Nor is steal% when specified for CO an average of CO/BTN/SB. If you tick position CO in the HUD Editor, it gives you CO only, not an average.
In general PFR is not very good for defining ranges. For example, he will raise 88 from CO, but if MP raises, he just calls 88 and this doesn't count for PFR even though its in his open raising range.
I have PFR in my HUD but only to see when someone is way out of line overall or super nitty overall.
RFI (Raise First In) is a much better stat to assess peoples ranges when they raise first in (seems pretty obvious but some people still rely on PFR), I put EP,MP,CO,BTN,SB RFI in my HUD and find it very useful, as you learn much more than VPIP/PFR.
Yes, 4bet% is unreliable without positions. But takes so so many hands to get reliable positional 4bet% stats. Better to just go off gameflow, range guesses which are usually pretty decent and what you've seen them 4bet before (notes).