The NEC is very near the airport about 15-25 minutes by car from centre of Birmingham (depending on traffic), on the list you will see some eg Holiday Inn Express located at the NEC, otherwise an airport location would be very near.
There are also good rail links into the centre of Birmingham...it depends whether he is attending a Trade Show and just focussed on that or whether he needs to go to a decent restaurant in the evening.
There are a few hotels actually on the site of the NEC/Airport/Railway Station and literally walking distance to the exhibition halls. Slightly further afield is the HOliday Inn Express which would be comfortable and reasonable. Or there's loads in Solihull (5-10 mins away)
how long is he there for and does he want access to bars etc? Bear in mind all the ones within half a mile and he may be disturbed by air traffic. The Tri-Star for example is literally under the flight path pretty much at the end of the runway