In our eyes, the most important issue here is the personal, educational one. I would not be happy if my child was – as this child apparently is – obsessed with getting paid in situations in which children in his situation usually do what he does without pay, and beyond that, argues about it with his friend’s parent. If the child’s parents are involved healthily in his character development and interact reasonably with you, it is worthwhile to discuss the matter with them for the child’s welfare. It would be best if you and they together develop a practical plan to deal with the matter.
It might be best to pay the child something, so that he does not feel that adults take advantage of him. On the other hand, he might be well-served by being put in his place. We are not child psychologists, nor do we know the child in question, and we therefore cannot give clear recommendations about what is best for the child in this situation. We trust you to handle this important matter wisely and sensitively – again, preferably in conjunction with his parents.
Regarding the halachic element of the question, we cannot tell you anything that you could cite as a ruling, as we have not heard both sides. However, since we do not suspect that you are going to a din Torah or to a court case with this child, we will discuss the matter with you, emphasizing that this should be taken only as a point of reference for you.[1]
There are two elements that can require one to pay for work done on his behalf: one’s agreement (explicit or implicit) and being a neheneh (gaining benefit from the work).[2] In this case, the would-be employer (you) did not agree (and even refused) to pay, thus precluding payment based on agreement. On the other hand, the would-be worker (the child) did not waive any pay due him (and even demanded it). Therefore, if it is objectively due to him as a result of neheneh, he should deserve pay.
The Rama[3] discusses the case of one who was in jail along with a friend and used his resources to secure the release of both of them. The Rama writes that if he needed to add resources to include his friend in the release or if he used his resources with the release of both of them in mind, his friend must pay him. The Rama then presents a general rule: “In the case of anyone who does an action or a favor for his friend, [the friend] cannot say: ‘You did it for free, because I did not tell you to do it,’ but rather he must pay his wages.” Therefore, to the extent that you benefitted from the child’s work, you ostensibly would be obligated to pay.
One could argue that the Rama’s ruling is not applicable to your case, because he refers to a case in which the recipient of the favor said nothing in advance regarding payment, whereas you said explicitly that you were unwilling to pay. The Pri Tevu’ah[4] mentions that possibility, but he rules that if the worker intended to get paid and there was a situation of neheneh, the recipient still ordinarily has to pay. On the other hand, Shut Mahari’a HaLevi[5] says that it does not make sense that one must pay after he explicitly told his counterpart in advance that he refuses to do so.
Given the fact that there are differing halachic opinions, it would be difficult in such a case for the worker to extract money in beit din, but that does not necessarily give one of whom the money is being claimed a moral “clean bill of health.” The Pitchei Choshen[6] claims that the Pri Tevu’ah was discussing a case in which the recipient of another’s work expressed only dissatisfaction at the idea of paying and also wanted the work done. In contrast, if he conclusively refused to pay, all would exempt him. This distinction might be further reason to exempt you in your case.
There might be another reason to exempt you. Considering that the work was being done by you and your children, as opposed to hired help, it seems likely that it would have been done anyway without your spending any money. Thus, from a practical perspective, there is little[7] or no halachically relevant benefit for which to claim.[8] Therefore, any payment would be minimal.
Another complicating factor of the child’s claim is that if anyone has a halachic right to receive payment, it is likely the child’s father.[9] Thus, if the child’s father does not want you to pay, you certainly would not need to.
We will conclude by emphasizing that independent of the actual halachic question, what is most proper to do in this case is what will ultimately most benefit the welfare and development of your son’s friend.