Is it permissible to sponsor an orphan and give charity on behalf of a living person without their knowledge?

Sponsoring an orphan is a great act of devotion. It is permissible for whoever sponsors an orphan to dedicate the reward of their sponsorship to whomever they wish among Muslims, whether living or deceased. This falls under the category of charity and similar acts whose benefit reaches others by scholarly consensus. If the sponsorship includes complete care of the orphan, it appears that its reward also reaches others if the doer intends it, because it is not purely an act of worship, but also involves a financial aspect and allows for representation. While the reward does reach others, it is better for a Muslim to keep the reward of their deeds for themselves and to supplicate for whomever they wish among the living and the dead. For it was not the custom of the predecessors to dedicate the reward of their prayers, fasting, Hajj, or recitations to their deceased.