Is it permissible to perform ruqyah on a disbeliever with the intention of inviting him to Islam, while informing him that healing is by the will of Allah and not by the power of the ruqyah?

There is no harm in a Muslim performing Ruqyah (definition) for a non-Muslim, for the Quran is a healing, and Ruqyah is a means for healing, and Allah is the Healer. This is as the Prophet, peace and blessings be upon him, approved of the Companions performing Ruqyah for the chief of a tribe of disbelievers who had been stung by a scorpion, and he permitted them to take a wage for it.