short answer: CALL.
Lets think about his range. He probably calls preflop with weak Ax, smaller broadways, suit connecters and small pocket pairs. His range preflop is capped, he shouldn't have strong Ax
hands or strong pocket pairs, you can definitely assume that he would raise them.
Now your range is not capped. You have all possible strong holdings in your range but also, since you are raising over the limper, your range would be somewhat wide. In short, you will have a lot of Ax hands that you will check on the turn, in your checking range AQ is actually near the top of your range. if you fold AQ, you would be overfolding in this situation, and villains will make auto-profit on you just with betting any two on the river. Your blocker makes it even easier. Villain has a lot of weak Ax hands that he could bet like that.
Also, another factor is betting size. Imho it is too small, which usually indicates about merged range. Which is good for you. Though in this situation he showed flush, usually people bet bigger with monsters on the river.