My Friend's Brother-in-law is on Tinder.

Problem/Goal: My childhood friend's sister's husband liked me on Tinder. Should I anonymously reach out to my friend's sister and inform her of what I know? Of course, minus the assumption and only by presenting details I have.

Context: I recently joined Tinder (just yesterday, in fact), and I found out that someone who looked familiar liked me. At first, I wasn't very sure because the guy (the husband) and I never really interacted (he doesn't know me at all) but I saw him a couple of times with the wife and multiple times on social media. I suspected it to be my friend's brother-in-law and I wanted to confirm. I took a screenshot of his profile for my own reference and stalked my friend's sister (the wife).

Now, before you come at me about him possibly being a poser, take note of these: his profile was verified, and the details such as his name, location, educational background, and job were accurate. I did my research very thoroughly because I really, really wanted to confirm my suspicion. Even though his profile said "looking for new friends," I found it very strange. Do you honestly believe that Tinder is used to find friends? Why would you like someone whose profile explicitly stated that she's looking for a long-term relationship if a friend is all that you want?

I really want to reach out to the girl because she deserves to know if something is going on behind her back, but at the same time, I've seen her posts on social media. She looks so happy and in love with her husband, and I don't want to be the reason that something so "beautiful" in her eyes end. They only got married last year after a year of dating, and as far as I know he is her first boyfriend. So, I do feel quite bad if something really is going on.

I thought about different scenarios while I was thinking of an approach. My initial thought was maybe she was aware of the existence of the account and they are polyamorous and are looking for a third (but then why would she choose her brother's friend?). My second thought was maybe she's aware of the existence of the account, recognized me, and wanted to check if it really was me or a stranger using my pictures. My third thought was telling her brother (my friend) about it but I decided against it. I do not want to cause family drama, and I wanted less (known) people involved.

Previous Attempts: So far, I have a draft written up and I have made an Instagram dump account for when I decide to message the girl. Rest assured that the draft I have written is sensitive and respectful. I, of course, did not include any assumptions that I may have and stuck with a factual message. I explicitly said in my message that I don't want to assume anything or cause unnecessary worry. I'm not trying to interfere, but I thought she'd want to know so she can look into it if she feel it's necessary. I also offered (in my message that I have yet to send) to share screenshots of the profile and a link to it if she's interested.