.
your in the BB loosey-goosey-fishy player makes it 600 to go from MP blinds are 200/400, he's liable to get all his chips in with any 2. Played against him on a number of occasions he perceives you to be TAG, in this session he has seen you play 3 hands in 90 minutes. AK, AQ, AA you have won one pot and lost two. you call the extra 400 and the two of you see a flop.
The half min raise would set off alarm bells for me. He's so desperate to get people into the pot that he makes an illegal underraise. I put him on AA+....hehe only joking I guess you meant 100 200

Anyway, here are my thoughts on the hand.
I think you should be re-popping him preflop with A-K. He's a loose player and has any two cards from your description. You're a solid favourite here and I'd make him pay to hit with his bag of random gonads. Although a 30 BB shove seems like a lot I think it's not that bad. You add over 10% to your stack, and given your history with villain and his loose nature he is I'm sure very capable of stacking off with hands like AJ AQ AT here, and possibly worse.
Flop comes down as 5 J K rainbow, you check your TPTK - you have this loosey goosey player on 22 - 99, A8 + you check the flop he leads out for 1500 with 1300 in the pot. Immediately your rulling out 55 - thinking something like 77, 88, 99 and you push for 5100 more hoping that he leaves it be and you can slowly start to rebuild a stack.
He starts humming and hawing telling you he thinks you have a K, especially after all the talk before i know you have a K he says but I only have 15 x BB here I have to call he sticks it in and turns over AJ.
Logic? He knows he's behind does he think he might have extra outs with the A? Does he put me on KQ, KT, surely he doesnt call if he thinks I have KJ. Given that for much of the previous 90 minuts you passed your BB willingly to any raise.
After you flat call, I don't mind how you played it, check raise his likely continuation bet BUT I hate this bit!
"Immediately your rulling out 55 - thinking something like 77, 88, 99 and you push for 5100 more hoping that he leaves it be and you can slowly start to rebuild a stack."If you really think he has a hand like 77 88 99(not sure I would given the action but you know the player better), you desperately want him to call. He has 2 outs, you are very unlikely to find a better spot to rebuild your stack than this. It's better than AA v KK preflop... As it is, he gives a horrible justification for stacking off with 2nd pair and calls. Happy days! You can go through various reasons why he might have done this but prob best to just stick with the fact that most players who play poker are rubbish and are desperately looking for reasons to get into bad gambling spots.
(I assume he won the hand though?)
One more thought.
Just before the restart the table is having a conversation about the hand you where in previous that seen your Aces turned over by J 7 you where making the point that it was a donkey call from the player because he must put you on a hand with your table image you then start remiding the table of the 3 hands you have played.
I know you were pissed off you lost with your aces but you should encourage this sort of play, especially if you are playing very rocky. You want a loose table which will give you action on your big hands and berating players for overplaying stuff like J-7 is usually not the best way to do this.
Say things like "Wow it was a brave move but man it paid off. You got a mighty pair of cojones on you there kid, good job" and maybe give him a playful punch on the arm. As long as he doesn't think you are coming onto him, he'll feel all relaxed and happy making stupid plays and generally giving his money away.