I kinda doubt that this is possible but with that being said, nothing ventured, nothing gained
My brother is coming up from London to see me in June/July, and I was wondering if I book a one way ticket to be on the same flight back down to London, will I/ or BA be able to merge this under one booking, and if so, would it also give him some of my perks of BAEC gold such as choosing seats now and additional baggage(allowance), etc…
Any advice is much appreciated

- J