Single page target 10+ services keyword.

Question for you guys, I have a friend who owns a website that already ranks well for a geo-targeted keyword, like *'plumbing services in Mumbai.'* Now, he wants to target all his services on this single page, such as *'Water Leak Repair Service in Mumbai,'* *'Washing Machine Installation in Mumbai,*' and 10+ other similar keywords. However, he doesn’t want to create separate pages for each keyword. How would you handle this situation? what I should suggest him. without hurting SEO.