I had a client like that. Every application included 10 minutes of hand weeding. Worked out fairly well.
Eventually he permitted me to spot spray weeds in October, if I used a really safe product and used less than 6 ounces of solution.
Eventually I was allowed to use Quicksilver, because I used only 20 drops of chemistry in a hand held sprayer. The toxicity is about 100 times less than Weed b Gone.