Hi everyone. Sorry, let me clarify my original question as perhaps I wasn't too clear.
My partner and I are both BA executive club members with individual accounts. I am the Head Household account member, and he is a member of my household account. AFAIK, our miles are not pooled. We hold them individually.
What I would like to do is transfer enough miles to his account so that he can redeem these for a flight. That's because he has hardly any miles, and I have just enough spare

My brother is getting married later this year in Hong Kong and this is the only way we can afford to fly this year -- so I am really hoping to be able to gift these miles!
I hope this clarifies my original question?