Whoa! Provided you (or she) picked up the poo, then there should be no problem. Although it is not ideal it is only a problem if your child or dog eats the poo with the worms in it. Unless you saw evidence of worms in the poo, although the dog has not been wormed it may not have them anyway.
Recommend she gets it wormed every six months. If cost is a problem perhaps you could offer to help her for your own peace of mind - certainly cheaper than getting your garden returfed.