Yea, went over there today and noticed the customer has a lot of his neighbors water running into his yard. They are above him on a hill, so their water washes into his lawn. We are thinking to put a swale or dry well at the top of the hill running parallel to the picture (not going down the hill) and divert the water to the edges of the yard and see if that helps. Then a lot of mulching / ground covers and landscape shrubs and small trees.
Any ideas are still welcome,