well unfortunately you can talk to 2 different reps and get two different responses...
does your friend have an evo 3d? if they have another handset then this kind of gives light that its not a handset issue and rather something on the network.
I have seen people post of delayed messages so you may be experiencing what some others have experienced..
Sprint sms delay
Sprint Community: Severely delayed Text Messages/Calls
Sprint Community: Text message delays/missed calls on Evo
Sprint Community: Text message delay
Sprint Community: SMS delay between Sprint and Verizon