OH says probably not, he says it's a town car and won't have the guts. Have a look see if you can find it here http://www.cuddles.abelgratis.net/kerbweights.htm
Just checked, it's not there. However if you have a read there is some useful advice on how to decide on safe towing weights.
Bit like wearing a seatbelt really isn't it? If it's safe for a short journey it's safe for a long journey, and vice versa.
Personally I wouldn't risk my life. and that of my horses, in something that isn't ideal. I'm not being horrible, I just wouldn't push my luck with something so important. Plus, if it's right on the limit it won't do your brother's car much good.
Just bought a Bateson Deauville which is 850 kg and will be towing a 600 kg horse with a ford galaxy (haven't tried yet). This has a max towing capacity of 2000 kg and I'm SH...ING myself as I know I'm pushing the boundaries. Having nightmares about running out of "puff" on a hill!!
Also will be very choosey about where I go so won't get stuck on wet ground. Hoping to change to a decent 4 x 4 next year. Sounds like the qashqai isn't the right one, sorry