I think your range calc is way too narrow here fnord, he also could be on a complete bluff. There is $13 in the pot and he risks $18. This bluff will work probably 3 out of 4 timess, definitely EV+ to bluff here. Heck, if ppl are laying down bottom two he theoretically has 95% chance of the bluff working!

I use this line myself in blind wars after I started noticing ppl re-raising my cbets after a SB or blind raise.