Gosh Dale,
So sorry your client had to go through this....

.
I will say for the record, that by the hour or contract...there are bad apples out there that do poor work and take advantage of folks like you client.
I still profess that "professionals," in most guild crafts and related occupations, work by a set metric (contract) and what clients really need to have before hiring is really only 3 major parts:
1. References with photos of work done.
2. A set contractual price or ceiling of maximum amount the work will cost.
3. A pay schedule of no more than 1/3 up front and final payment(s) are held to job completion and satisfaction.
Those little steps in vetting contractors would save this kind of thing from seldom happening...
Your client is lucky to have you come back to help.
Regards,
j