My son-in-law and a employee of his bought a house and flip it they wanted me to rewire the house for them the agreement was they would reroof my house labor only when the time came to reroof my house the only person that would help is my son-in-law the other party refused to help we had nothing in writing it was verbal but I have several persons that know that this was the deal,Do I have the right to a case for his half of the labor?

Yes

Yes, you would hire another person to work, and use his bill for the time as proof of the labor amount spent. But yes you may sue him for the value.

Or or course since you son and this person had the agreement, your son may also have standing to sue him, since you could since it was a partnership, your son has some liability to you for his partners labor.

My son-in-law and a employee of his bought a house and flip it they wanted me to rewire the house for them ...

Look into the possibility of filing a mechanic's lien against the house. Depending on how much time it has been since you did the work, that might be a possibility.