Mind your own business is what I really want to say

I think “You’re breaking up” and “I’m running out of battery” might do it?

How will he even know you helped her ?

Evasive answers are the way go, I think. Aggression would get you nowhere other than hurt and uncomfortable. When he asks specifics (how rude!) you simply need to cover your answers with 'can't exactly remember' or 'bits of this'n' that'. Perhaps you can refer him to your husband if he can handle him better.

Why does he actually need to know? My brother has never asked how any of our DC bought a house. He has only ever been pleased for them (we never helped them). I would never ask about my niece or nephew buying a house. Again I would be pleased for them. Just say they got a good deal or something.

My response would be, to the first query he raises us “Why do you ask?”
Answering a question with a question is a good swerve!
If ferl compelled to answer just be economical with information.
You could feign that you don’t know how she afforded it, followed by “in any case it’s none of my business.”
For example,
When I get asked about my DD not having children I just say “I don’t know and I don’t like to ask because it’s none of my business”. That soon shuts them up.

... buy your mother her own mobile?

And cut him out of the conversations all together.

You can get one of those 'big-button' simple-to-use mobiles which are quite popular, unlocked and pretty cheap, if you think she's not able to manage a smart-phone.

And frankly, politely telling him that your financial arrangements between you and your DD are a private matter is not rude.

I would tell him that you don't feel it necessary to offer an explanation of how you "managed to afford it". If he's not in any way involved financially, then it really is none of his business.

... or, tell him that you forgot to mention you'd had a huge win on the Lottery and bought your DD a house with it and... "can I speak to Mum now, please" .

You don't need that kind of pressure, and shouldn't have to put up with it.

Nonogran

When I get asked about my DD not having children I just say “I don’t know and I don’t like to ask because it’s none of my business”. That soon shuts them up.

... how rude, and what an intrusive question for people to ask you about your DD. Prying, probing busybodies really are the pits.

We managed quite easily would be my answer for both questions. It really isn’t any of his business and don’t tempted to explain anything. Yes, a bad line breaking up works wonders too. Good luck.

Agree with Elaine1 - if he asks, say "why do you want to know?" My mother had an inquisitive relative and sometimes used this tactic. It needs to be said in a non-aggressive way, as if you are just curious.

Why not just ignore the question and follow up with something anodyne about the house

Bro: How could she afford that? How much did you give her?
You: Yes, it really is a lovely house but she will need to redecorate to get it to her house

And do that everytime he asks.

Listen to any politician being interviewed, you will soon get the hang of it.

Sorry, it was Nonogran who suggested "why?" but Elaine and others have good ideas too.

As he’s a mean person I would tell him oh, the money was just sitting in the bank, we don’t need it and they may as well have the money now instead of waiting ‘till we’re gone
I really really hate mean people so when the opportunity arises to wind them up, I do.

Don’t I remember you from a while back? Obviously Mum still hasn’t got her own phone. Why not just tell him he’ll have to ask your daughter about the house as it’s her business not yours. And do get Mum her own phone!

You could just tell him to mind his own business; I would.

Some great answers here. I am ready!

Maybe if he does you could say something simple like she's careful with her money, isn't it lovely that she has been able to get herself a nice place
If he persists, maybe say are you wanting to make a contribution, I find you her bank details if you want or maybe you could just pop a cheque into her Christmas card lol

I hate controlling siblings

Smileless2012

You could just tell him to mind his own business; I would.

Me too ?

If he is rude enough to ask, then I don’t think any of the answers you’ve quoted are rude. It is, as you say, none of his business. I wouldn’t tell him that you’ve contributed - it’s not relevant. If he assumes you have or if your DD lets it slip and he asks, then I think that’s the time to firmly tell him that the details and reasons are between you and your DD.

M0nica

Why not just ignore the question and follow up with something anodyne about the house

Bro: How could she afford that? How much did you give her?
You: Yes, it really is a lovely house but she will need to redecorate to get it to her house

And do that everytime he asks.

I'm with Monica. Just refuse to answer. If he keeps on asking, in the end just say I don't really want to discuss it. Nosy beggar!

A friend of mine always avoids answering anyone’s nosiness by saying ‘Oh don’t ask’, in a jokey , polite way? It usually stops the conversation in its tracks and then changes the subject.

Farmor15

Agree with Elaine1 - if he asks, say "why do you want to know?" My mother had an inquisitive relative and sometimes used this tactic. It needs to be said in a non-aggressive way, as if you are just curious.

... "why do you want to know?" That sounds like a good tactic!

I'm curious about your name... "FarMor" is a Swedish abbreviation for "father's mother"!

Well I would say it’s none of your business