According to MLBTR:

Pirates Designate Chase d'Arnaud For Assignment

Well, I am not sure I have even heard that he had a brother, much less an older brother that has pulled MLB service time.  The infield version, CDA, is a career: .261 .339 .397 .736 in 6 minor league seasons and .208 .232 .275 .507 in 57 games on the MLB level.  He is quick having a 13/2 SB ratio at the MLB level and 153/32 at the minor league level.  Based on stats, he doesn't seem to have much pop but does have some gap power with a couple of 30+ double seasons. Early in his career OBP seemed to be like his brother, a strength but he has struggled the last couple of seasons. 

The best thing about CDA appears to be his versatility.  Having played mostly SS, he has also logged time at 2B, 3B, CF and LF.  Would bringing him in to throw into AAA utility role be such a bad thing?  Would having him around make TDA a little more comfortable?  Do we want him more comfortable?  He certainly hasn't earned the sign my brother pull that Glavine once was able to pull off but I do not really see why a minor league contract wouldn't be worth the risk.  He does still have 5 years of control remaining, I think.