Haha sorry, this thread seems amusing to me..couldn't help but
have a few chuckles. Just reaffirms the fact that as people age,
they tend to become childish in many ways. you should really tell
your husband about it and next time you catch your FIL doing it,
just tell him: "Pa! Mai pak chiu ceng la!" And if you catch him
peeping at you, just confront him and expose him. Some people,
including the seniors need to be put in place when they step out of
line. Nothing really disrespectful, more like out of necessity.
yeah...i can't help but giggle too.
tiam tiam is probably the best thing to do. I think if tell
husband, probably will become family news. He'll probably ask, "r u
sure or not? Maybe he was putting mopiko for mosquito bite!".
FIL's business, but like Rockstar mentioned, the peeping at
you is not proper, so tell him to stop being so chiko. 
