I cannot comment on the story because I have no proper reference to the origin of the story. Even if the report from Rabi' is authentic it is not a source of religious knowledge for us. In Islam only the teachings of the Prophet (sws) in the form of the Qur'an and the Sunnah form the sources of religious knowledge. Dreams are never a reliable source of divine knowledge. Anything including dreams contradicting the teachings of Islam has to be rejected.
We can, however, discuss the act this person has done and see if we can do that in extraordinary circumstances. We believe that though the Sunnah of sacrifice (Qurbani) has not been held obligatory for the believers it is nevertheless extremely important. As regards the question of abandoning the practice for some other important work of individual or collective good it is left on the individual to decide. For example one needs to be aware of the importance of this worship ritual and should try his utmost to offer an animal for sacrifice but he may sometimes while intending to do this abandon in order to fulfill another urgent obligation. For example if I have some money saved for the purpose but am approached to by some friend or neighbor who has to wed his son or daughter and he is really in straits enough to discharge this duty I may try to help him out leaving the offering. This is not standout to given priority to that matter over the ritual of sacrifice (Qurbaani) rather it is a proper response to a more demanding situation. God the Almighty is extremely merciful and He may reward me on the acts, the one I intended in the first place, and the one I have opted for realizing the gravity of the matter. This should not be taken to mean that I give no importance to the ritual of sacrifice or consider it a wasteful activity but it should be read as my proper response to a needful event. This is how we behave in our life. Many people try to save money so that they can avail a hujj journey but cannot do so in the face of some urgent and more important personal or social need. We cannot however draw a principle from this example and say that offering an animal for sacrifice is rather a useless act and we should look for spending in some other cause. We need to fulfill both kinds of duties and it is only when we have no way out regarding another problem when we can postpone sacrificing an animal.