Family researchers at http://www.rootsweb.ancestry.com/ indicate Hardy was an older brother of Thomas Broom.
In addition to his service in the 46th. Inf. Thomas is also listed with Hardy as members of Company G (Marion Grays)
3rd Brigade, 2nd Reg. Mississippi Militia. (See 2nd. (Quinn's) Regiment at this site http://mississippiscv.org/MS_Units/minute_men.htm)
Luke Broom, brother of Hardy & Thomas, is also listed as a member of Company D (Covington Farmers), 2ND (QUINN’S) REGIMENT MISSISSIPPI INFANTRY MINUTE MEN.
Hardy and several more of the Broom's are noted at this website.
Hope this helps.