How to respond to BIL’s unwelcome behaviour?

[Smudge100]

Since my divorce about six years ago I have become closer to my older sister. Not that we were estranged, simply that ex-DH wasn’t interested in my family and didn’t want to visit/have contact. I always had the impression that DS had a strong and intact marriage (of 20 years standing). I have not remarried/found a new partner and at 62, I am quite happy living on my own and am not looking for anything beyond that.
A while back BIL (who is older than me) came to stay for a couple of days to do some work on my house (he is a retired builder). Thereafter he started to send me chatty emails about what he and DS were getting up, what was growing in the garden, bla bla all very nice and entirely innocuous. No problem, although I thought it a bit odd that he was emailing me every other day when DS only emails about once a month. However, in one email he said that when he was staying at my house in the guest room, I had left a pair of lace knickers on the floor – (this didn’t happen btw, who leaves pants lying on the floor of the guest bedroom???) – and he had found it a ‘turn on’. Shortly after I had another email saying he hoped I was looking after myself and had I had my breasts checked by the GP? I was horrified and blocked him. A couple of weeks ago, he and DS stayed over on the way to somewhere else and he was perfectly fine and well-behaved, so I unblocked him, thinking that maybe he had learned his lesson and was going to behave like an adult. The chatty, friendly emails recommenced. However, in response to an email in which I related how I had overcome a plumbing issue and had been able to have a bath again, he responded: ‘sorry I wasn’t there to wash your back’.
My question to Mumsnetters is, what do I do now? Do I block him again or do I call him out on his disgusting behaviour? I absolutely cannot involve my sister because I do not want to compromise her happiness. I fear that if I challenge him, he will badmouth me to her and I won’t be able to tell her the truth. I think that’s what he’s banking on. I feel that I will end up being the Bad Guy in this situation whatever the outcome. I just don’t know how to handle it. I can’t believe that at my age I am having to deal with this situation. What do you guys think I should do?

The only thing that you’ll achieve by telling him to stop or you’ll tell your sister is that he’ll find someone else to try it on with.

Those messages are incredibly bold, especially given they’re to his wife’s sister. Do you really think someone who indulges in such risky behavior is doing it as a one-off?

Reblock him and continue a distant relationship. Don't involve your sister and stop giving him chances.

This^^

I'd reply saying this is totally unacceptable and unwelcome. I'd add that you have looked over all the emails that you have both sent and there is nothing there to lead him to think that you find him in anyway attractive, that way there is the underlying threat of having the email chain without being explicit. I understand not wanting to tell your sister but make sure that you keep his emails just in case it comes to a head.

I completely understand why you feel you cannot involve your sister but my concern would be that he is doing this to other women as well and they might be taking him up on it compromising your sisters marriage and her health (if he is having affairs). If it was me I would tell her, but I do understand why you wouldn't.

i'd suggest that if he's bold enough to try it on with his wife's own sister (without any indication it might be welcome), he's definitely tried it on with other women.

in which case, i don't think it's fair to your sister not to know what she's involved with.

however, if my brother's wife tried it on with me, in all honesty i'm not sure i'd tell him. but i would be telling her she was being ridiculous and selfish, and if she had that little respect for my brother/their relationship, she should deal with that properly.

could he have dementia?
can't that make some people behave innapropriatly

Or Alzheimer's.
scroll down on this website it mentions innapropriate flirting or sexual advances.

www.cbsnews.com/pictures/alzheimers-25-signs-never-to-ignore/

I think you'll need to have a gentle word with your sister just in case it's one of these things.
Check out the rest of the list perhaps he exhibits a couple of other behaviours as well so you could use those to start the conversation.

Have you approached him about the emails?