Is $6,100 to remove popcorn ceilings and paint them a fair price?

I am a first-time home buyer. The sellers agreed to remove PB piping throughout the 2290 sq ft house. A plumber suggested removing the popcorn ceilings and painting them because blending the holes from the pipe removal would be difficult. I hired a family friend who quoted me $6100 for this work. He started on July 25th and was supposed to be finished by August 14th, before new carpet was installed and cleaners arrived. The work was not completed, and the quality was terrible. Cleaners refused to work, stating it was a post-construction clean costing around $3500. I told him to leave on Friday afternoon, less than 24 hours before my scheduled move-in on August 16th. He is now blaming me and demanding the full $6100, though I've only paid about $1000 for materials. I am disappointed with his lack of ownership and the situation, especially after he offered to be a 'male figure' after my father passed. I am willing to learn about drywall but will be traveling for 2-3 months for work. This has been a very stressful experience during my home buying process.