To be this irritated by this habit?

[yummyicecream]

My brother answers for other people when I’m speaking to them.

So an example, I showed DH a photo on my phone of DD and held it up. Brother was sitting across the room and when I said ‘awe isn’t she cute’ shouted ‘yes she is’ in that sort of monotone not listening tone (and was looking elsewhere at the time.)

Or I will ask someone a question that they know the answer to (eg to FIL ‘when are you off to Devon?’ and he’ll shout ‘I don’t know.)

I know it sounds really petty but it alienates me from a group because I literally can’t talk to anyone.

I don’t need advice on dealing with it S such I’m more wondering if it would annoy others as much as it does me?

Get him to move out. It will drive you nuts.

You could say "FIL.you answered that question without moving your lips!" And just make the same comment every time so your brother starts to see a pattern.

But what a weird thing to do. When's he moving out?

It would drive me nuts but then your whole family sounds very annoying.

You ask FIL a question, brother jumps in with “I don’t know” FIL just doesn’t answer.

You ask your DH a question, brother jumps in with “I don’t know”, DH doesn’t answer.

The others should ignore brother as his response is totally irrelevant so why don’t they just carry on and answer you?

I would definitely have lost it with at least one of them already so you must have the patience of a saint.