What is the ruling on supplicating against someone who is not an oppressor, but rather oppressed, on the claim that a doctor gave him medicine and it did not work for him?

"Supplicating against a doctor or anyone else who is not oppressive is forbidden and constitutes an aggression in supplication, for which the doer is sinful. Moreover, such a supplication will not be answered, because Allah does not respond to a supplication involving sin or severing ties of kinship. The one who made such a supplication must repent to Allah, and it is better to supplicate for that person and seek forgiveness for them."