As I have mentioned before, around 1983 I did not use all of my allocation of priv. tickets one year (the only time it happened) and as a joke applied for one from Rodwell to Crowden (closed 1952 and 1957, respectively): it was issued.
Going back to the original purpose of the thread, I can’t see how a relative could be supplied with a priv. ticket without a considerable risk of the user being stopped and possibly questioned, and a risk to the member of staff of facing disciplinary action. Even if the purchaser could trust the traveller to keep schtum, buying a priv. rate ticket over the counter and handing it over would risk them being stopped en route; there could still be further investigation to find the purchaser.
As said, I left the railway in 1987 so I don’t know if inspection practices tightened up after privatisation. On BR I suspect that booking office staff would probably want to see the card of someone they didn’t know to check their entitlement, but once you had the ticket, inspections would probably be much slacker, but you could still meet some who were much more thorough. I knew someone who caught a very senior member of regional management without his pass on his commute, even though he knew who he was.