Mac Pro GPU Upgrade

[agentbb007]

My brother wants to upgrade his Mac Pro 2009 versions GPU. What card would you advise? I was thinking this GTX 750 card. Here are the specs of his Mac.
https://support.apple.com/kb/SP506?locale=en_US
http://www.newegg.com/Product/Product.aspx?Item=N82E16814487094&leaderboard=1

 

[Ezo Legendz]

Has he ever thought of just getting rid of a mec if not yes gtx 750 is ok if you can afford it 750ti