No signed contract. Only verbal. Wants us to pay for milage, labor, and other things

We bought a house last year. My wife’s step father and his dad did the work. We have a verbal agreement to pay for material costs (approx 11.5k) as time went on other tasks were completed (he’s wanted/agreed to do them with the same verbal contract). It got to a point where they then abandoned the project all together. With some convincing I got the ‘grandpa’ to finish the heating and cooling part of our original verbal agreement. As to date we have paid him 21k for material (and some gas/toll costs) to keep the peace. He now wants 5k for labor, 5k for materials, and 6.2k for ‘travel’. Is there anything I can do since there is no signed, no written, only verbal contract. I can elaborate on anything if needed. Thank you