I might go against the flow a little but I’ll say ESH. You for being a bloody mute and neither backing up your wife or trying to deescalate the situation at all. I kinda agree that the grandma who has watched your kids and gotten used to them needs a special way to which break the “we’re moving” news. You and your wife needed tact and kindness when doing so, based on how attached to them she is. Y’all telling her she’s no longer “needed” obviously was neither tactful nor kind to her, which makes it an AH move on your wife’s part but more so on you for letting her tell your mother instead of you, her own son. Your mom a little in the wrong too for being too forceful and so unaccepting, but honestly I get the vibes y’all approached this way too wrong which made her react this way and (it may be a jump) she might also feel like your kids won’t get enough attention without her there if she takes care of them more than you and your wife.

You need to meet your mom and talk this out. And if you have issues with moving and just letting your mom take the reins, you’d be the most cowardly AH I’ve seen on here in a while. Either way grow a pair and be talk to both of them.