I admire your restraint and for giving her the chance to try and soothe him herself.

She just doesn't want to let him go and wants him to get to know her so he can be soothed by Grandma. And it could also be that she thinks she's giving you a break by taking him and not just handing him back the moment he starts fretting.

But quite frankly if he starts getting worked up I would just pluck him straight out of her arms and say "oh is it time for Mum/Dad again." No quibbling, just cheerfully and matter of factly. And get your DH to do the same thing.

It doesn't need to be a drama and in fact it's great your DH has laid the groundwork by telling his Mum that if your DS gets worked up it's time to hand him back...keep up the momentum. She'll get the idea.

And as for the dummy...if he doesn't need it get rid of it and don't let her have access to it. Just tell her you've ditched it.

As long as she still gets plenty of cuddling time then I can't see the problem...it's hard at first setting new ground rules but most reasonable grandparents will fall into line when they see how you like things done.

The one thing you might hear is "but he has to learn to go to other people" so be prepared for that argument and hold your ground. He's only 3 months old, plenty of time for that, and it's not as if you aren't allowing him to be cuddled by anyone else other than Mum or Dad.

Good luck.