semanwen "Well you should have checked before using the name of her dead husband. Quite inconsiderate of you all round." What a crap comment. No one owns a name. The name is the name of the *OP8's child's father! He has every right to use his dad's name as a name for his child.
"Because not everyone is always at the same point about remembering the dead. It may well be that seeing the child will bring up memories that she doesn't want.
It is inconsiderate not to ask."
If she feels so strongly that the sight of a baby (who she is related to) brings back memories of her dead husband then I think she would feel that way even if he did not have the FIL's name as a middle name!
Imagine asking permission and being told no! Then having to choose between naming your child what you wanted or 'hurting' your mum.
There may be genuine reasons when using a name would be a bad idea. Like if the name had been shared with a niece or nephew who had died, or a close friend's child who had died. Then, of course, using that name without permission might well be wrong.
But actually a middle name is so rarely used, at the announcement of a new baby, at a baptism and when receiving an award! But not day to day.
I don;t think this woman is really hurt by the choice of the name, I think she is looking for a reason to be angry. But I have no idea why, and I would not want her near me or my new baby to steal my joy!