A hand vs. a friend

[jkamowitz]

NOTE: I enjoy playing against friends (as they realize it's nothing personal when either of us wins and they appreciate the good competition) However this day both my friend and I are running bad, not sure if that influences whether or not we are looking for easy spots to raise each other's big blinds.

So Borg 20/40 a while back.

Friend opens in LMP, sb is a decent pro who tends to pick on my friend and calls his raises lightly, more than likely counting on his ability to play post flop.

I 3-bet A[img]/images/graemlins/heart.gif[/img]Q[img]/images/graemlins/diamond.gif[/img] in the big.

Both call.

Flop K[img]/images/graemlins/diamond.gif[/img]10[img]/images/graemlins/diamond.gif[/img]3[img]/images/graemlins/diamond.gif[/img]
I bet and only my friend calls and shoots me a look.

Turn 5[img]/images/graemlins/club.gif[/img] I check, he bets, I call.

River 5[img]/images/graemlins/diamond.gif[/img] I bet, he raises, I call.

I think this hand is interesting as all streets are up for debate.

Questions that arise:

1) 3-bet preflop is obviously debatable and I have my reasons but would like to hear others advice.
2) Turn check is also debatable.
3) As is river bet/call line.
4) What does my friend have?