How to play 5NL micro villains who min bets into big pots on all streets?!?

First off, I know I know -- I shouldn't have 3bet 44 preflop, especially vs an EP raise. I know. The little I knew of him suggested he was loose passive, but couldn't say for sure. This illustrates, however, a pattern I see in the micros a lot, and it drives me crazy! Here goes....

Full Tilt - $0.05 NL - Holdem - 9 players
Hand converted by PokerTracker 3

LP: $4.95
CO: $1.17
Hero (BTN): $6.38
SB: $6.59
BB: $16.44
UTG: $6.07
UTG+1: $3.85
MP: $3.05
MP+1: $5.46

SB posts SB $0.02, BB posts BB $0.05

Pre Flop: (pot: $0.07) Hero has 4 4
fold, UTG+1 raises to $0.17, fold, fold, fold, fold, Hero raises to $0.50, fold, fold, UTG+1 calls $0.33

Flop: ($1.07, 2 players) 6 A 5
UTG+1 bets $0.05, Hero raises to $1.22, UTG+1 calls $1.17

Turn: ($3.51, 2 players) A
UTG+1 bets $0.05, Hero calls $0.05

River: ($3.61, 2 players) A
UTG+1 bets $0.05,
Hero.....???

I'm either 1) up against air, but the idiot donkey read somewhere that you should keep betting if you have a hand, and sometimes even when you don't, so he puts in these tiny bets (are these called post-oak bluffs, btw?) ... as if they would make me fold. Or 2) he has an A and is being retarded about it. No, of course an baby underpair wasn't great, but I didn't put him on AX w/ his actions on the flop & turn, let alone when the other 2 Aces hit on the turn AND river. There's no way this guy has that 4th ace and bet like that. So he min-raises $.05 on ALL streets!

Anyway, how do you handle something like this??? If he had checked I could have been more likely to check the flop and drop the turn w/ any betting from him (real betting I mean.) But that stupid tiny bet ... what the f--k is he trying to do? Be fancy? Be a donk? Mess w/ me? Take another swig of his whiskey and continue to play oh-who-gives-a-**** poker?

[Spoiler alert: he does NOT have an ace.]