Hand I observed and wondering if the play I saw was good or bad

Predraw: co raise, sb 3b, co 4b, sb call
1st draw: 1/1
Flop: x/x
2nd draw: 0/1
Turn: b/c
3rd draw: 0/0
River: x/b/r/c

Showdown: sb 95342, co 87542

Feels like too thin check/raise by villain. Also is flop not a bet for the co? What range is the sb giving the co here on the river?

On the river, do you think it's possible co is betting a worst hand and calls the check-raise?

On flop it depends what the co had, 7542 he should bet, 8542, I'm not sure if there's any point

Check/check on flop unimproved off equal draws is pretty standard.


When sb pats flop it's interesting because I imagine a few potential scenarios:

1. sb caught a 9 that would've broken if co bet(most likely flop scenario without additional information)
2. sb wanted to x/r in a leveling play vs a particular co who barrels unimproved there too much(whole value range)
3. sb wanted to x/r turn as a change up play(unlikely, range most likely N5-N12 mid strength range)
4. sb decided to pat snow with a bad 4c draw in a big pot once co checked back(more likely if co is foldy or straightforward)

Turn play just looks like co is most likely freezing sb because he assumed the 1st scenario above is the most likely and the pot is a decent size, Most likely freezing range is 97-87.

River play looks like a value x/r from sb. co rarely raises a bet there so his entire range should be checking as a standard as co's freezing range is overall ahead of sb's flop range there which is mostly 9s. sb's x/r range depends on his perception of co's betting range but most likely it means that the correct flop scenarios were actually 2/3 as I don't see him value x/r a 9 there, maybe a 95 which I don't think is good. If sb GTOs there it's also possible he is x/r a small part of his 98 range as a bluff.

A typical freezer will not fold anything to this x/r on the river because the probability of flop scenarios 2 or 3 are very low to start with so the relative chance of sb being on a spazz are too high. The freezing range is actually more defined as marginal than sb's range so the chance of a sb spazzing are not low.

I prob check back river if I were CO...and I would prob fold to a x/r. Very different obv if SB draws 1 on flop then checks pat on turn. What is worst hand SB should be leading this turn with, assuming he started w something different than 2345?