Over the past several years I've observed my brother-in-law (my wife's sister's husband) ogling my wife. In the most extreme case, he watched her change into her swimsuit through the window of a motor home. In more typical scenarios, he seems to find an excuse to approach her while she's in a visually-vulnerable situation (i.e.: nursing, swimming, etc.), and linger. It may be relevant that he is flirtatious, although my wife does not respond to it (not intentionally, although it seems he may have taken some of her actions as responses).
While I initially thought it may simply be coincidence, and tried hard to come up with other explanations (for my own peace of mind), I've observed enough obvious ogling occurring to accept that this is intentional. I doubt he would never cross the line of touching her or worse - this question is just about the ogling & flirting.
Here's the twist: my wife has only seen (or accepted) that it happened once (possibly due to her wishing so badly that it was not occurring, as it hinders her relationship with her sister). My wife's parents have never seen it either (they are wholesome, conservative, Christians, who would be shocked by it; but who also may be blind to it). To my knowledge, everyone else in her family regards the man in question as upstanding, and above reproach, and would never think he would do anything of the sort (he is, after all, a pastor). It is making me think I'm crazy... could I be mistaken about what I've seen?
Should he be confronted in order to pursue family unity, or is ogling harmless?