Glad it worked out for him. The only thing I'll add to the above responses is to not just check that there's a lounge with hours that accept your voucher, but check that is a decent lounge. Some lounges can be pretty bad to the point where I'd only go in because I have free access (and one or two I'd completely pass on), but others can be very nice for a priority pass/lounge key lounge, such as MCT (Primeclass), DXB (several options), and IST (IGA)