MercuryQueen
Smileless2012
He didn't know when he told his mum Sara, which is why he then told her not to let her d.i.l. know that she knew.
And THAT, imo, is completely wrong of him. He should be honest with his wife, tell her that he’d already spoken with his mother, but from now on, he’ll ensure she’s okay with whatever is being shared.
When she finds out (and she will, this stuff has a way of coming out) chances are she’s going to be hurt and furious with both of them. Human nature being what it is, the OP will end up wearing it, because they have to live with each other.
Indeed, the son should have told his wife when he spoke out of turn, perhaps he could be convinced to tell her now. Clear the issue and promise to never reveal private information again?
There seem to be other small issues as well. OP wondering at dil not visiting without son - apparently, she's not comfortable with his mum, visits with son make sense. Does son visit his mil alone?
And something I haven't sussed out regarding a GC seems to be a problem for OP. Perhaps she could clarify with her son?
I'd guess clearing the air with her son may help a bit with any small misunderstandings. And keeping a low profile, not pushing.