Your mother first needs to read carefully the written contract that she has with the contractor as to its scope and terms in that it sets forth her obligations to the contractor and vice versa unless state law controls.Although your question states that the contractor has been less than professional, you do not state what he or she has done for this opinion.Work for the improvement has been started. Apparently the contractor is not behind schedule on this project.If your mother does not like this contractor now for whatever reasons, she cannot end the contract without having to pay the contractor his or her estimated net profit for the project. If the contractor has breached the agreement and the breach is a material breach, then that is a different issue altogether.If your mother decides to back out of the contract just because she no longer likes the contractor, she will have to pay for the materials and the net profit that the contractor would have received on the project.The only way to get out of the contract with only paying for the materials is if the contractor is willing to do so and he or she signs a written agreement to this effect.Good luck.