BA will definitely reimburse him for his overnight in MIA due to weather or not.
If his IFE was not working at all on board and the crew were not able to offer him an alternative seat he will definitely be compensated for that also – the crew in fact would have been able to give him some Avios directly on the aircraft.
You are right though IIoydah – compensation or not it doesn’t leave a positive first impression. Please encourage him to claim for his hotel and complain about the lack of IFE though. Not being left out of pocket and a chunk of avios should hopefully soften the blow a little.
**These are my personal opinions only**