NetSquirrel, I can understand your concern for the welfare of the hawk, particularly as you say that your brother has has numerous 'exotic' pets in the past that have perhaps not been kept in suitable conditions, and have met an early demise.
Personally I believe that these sort of animal or bird should only be kept after adequate research into their care, which means reading books, talking to other owners, pet shops etc to get a good knowledge before even attempting to own one of these animals. It may also be that your brother needs a licence to keep the bird
Have a look at these sites
http://www.falcons.co.uk/default.asp?id=17
http://www.worldofpetsni.com/birdfalcon.htm
http://www.defra.gov.uk/paw/publications/law/2_9.htm
They all give very good information about keeping birds of prey.
I'd suggest trying to talk to you brother about your concerns, but if that's not possible and you have serious concerns for the birds welfare, then yes, I would call the RSPCA and ask for their advice.
Good luck.



