I wouldn’t tell anyone - I don’t think I’d even tell the kids because I think it would have a negative impact on them - I think they’d be better off in the early part of adulthood learning to fend for themselves, as that’s a very important life skill.
Not sure I’d tell DH - as I don’t want him telling FIL - FIL who hasn’t been part of our life for over 20 years will be on our doorstep within a few hours, expecting half.
When I was first living with DH (and not FIL), I’d bought a lotto ticket with MY money, and FIL told me that if I won, I’d have to give him half, and share the rest with DH’s siblings. No mention of my mum, my siblings, or MIL. FIL was quite serious and I was shocked at his entitled attitude - I soon learn how entitled FIL was when it came to government handouts and loopholes.
I do try to keep very quiet about my finances IRL. A few years ago I received an inheritance in dribs and drabs over a year, as the estate dealt with the assets. I had a coworker who was causing me grief with our manager, that I was unaware of at the time. Anyway, coworker was paying off a holiday that she was taking in 6 months. One day she started saying “omg omg omg”. I ignored her. Then she said “Omg I just checked how much was owing on my holiday, and it’s all paid off!”. Holiday was less than 2 thousand, so not really a big deal. I had to bite by tongue, but I wanted to say “omg omg omg, I just checked my bank balance and I have almost 200K sitting there!” - as one of my inheritance payments had landed in my back account the day before. I would have loved to see the look on her face, but kept it to myself.