pro biotics - same time as Ab's or after???

[rattlesnake]

Want to give DS a good probiotic. do I give it at same time as AB's? or is this pointless until he's finished course??

my dd was recently on antibiotics and pro biotics at the same time. Dietician had said that sometimes ab's can destroy some of immune system so probiotics at the same time just counter balance iykwim.
Sorry not much help really