Those saying your DH was out of order obviously have never been on the worse side of blatant favouritism!!
I have, in my case my mum gave DB 10s of £K for a house deposit, I got nothing. She blurted it out to me too, when Ill. 4 yrs after giving it.
I walked out (she was recuperating from a fall in a care home) and went NC for a few months incl xmas. Even then she tried to charge me £5 for using her phone when she was in the home. Words still fail me.
I dropped the NC when she was given a terminal diagnosis with months to live as I wanted to look back with no regrets. But guess which mug took her to hospital - it wasn’t golden boy who doesn’t drive!!
It is about more than money, much more. We had no need for mums money, we have earned every penny we have.
But I felt v much second best and a mug as I was doing all the running around whilst golden boy sat on his a**e.
At the time of mums fall a few weeks earlier, a relative who knew about the money and was sworn to secrecy, told me to “Look after your immediate family above all else”. I didn’t understand the message at the time but it became very clear a few weeks later.
That is what I will say to you Op.
Pull back, don’t visit, don’t ring, spend more time focussing on your own family, control what you can, which is not the grandmother. She will reap what she sows if her golden GC isn’t as attentive as you.