
I struggle to find the words to express how dreadful this must be for you and all those around you.
BA6501 has mentioned the Saudia site, the better one (currently) is the Qatar website, which definitely works for BA tickets beginning 125. You will be asked to give an email and telephone number, put something relevant in but it will then get you to the Booking Reference PNR on BA on the top line. I've just tried it with several BA bookings and I know it works.
https://booking.qatarairways.com/nsp...eBooking.xhtml
or
https://booking.qatarairways.com/nsp...rievePnr.xhtml
You then get the screen above.
You may also find he has installed the BA App on his mobile phone, that also has the information (and a cancellation provision, don't do this via this route unless you understand the implications but it simply gives a conventional refund at the advertised penalty rate).