Mother has custody of the child and father has joint custody of the child .Mother has left child with her parents for four days now. Her father(grandparent ) just contacted the father to let him know that she has not returned home and is recorded to have a drug problem in the past which was brought it the courts attention but since she was able to a pass drug test she was able for main custody. He can not return home till the 17th of December. What are the options that he has in the eyes of the law?

He can leave the child with the grandparents if he can't get the child. But for anything official ordered by the court he would first have to get a court date and that court date won't be before the 17th. Unless an emergency hearing is done but that isn't required. I'm not entirely sure what the question is... is there something specific that you are wanting to know? The law isn't something you can just ask a vague question like that and get option 1, 2, and 3.

Well first if they have "joint" custody she should not have "main custody"
In pure joint custody she would have the child one week, he would have the child the next week, or one has child for 6 months, then the other.

So exactly what is their custody agreement.

After that, he can file in court for an emergancy order to give him temp full custody, of course he will have to make arrangements to be at home to care for the child and not traveling all the time.