It looks to me like BA handled the situation well, but perhaps didn't communicate it so well.

If (and I'm assuming here) your elderly friends are anything like my parents, and not used to/fond of flying, to be told you're being kicked off your flight at 1130 at night, 6000 miles from home, will be a fairly harrowing experience. The fact they're quite lucky to get another flight so soon after the original, and on a better airline, is irrelevant to that.