As per "Dictionary of Basic Japanese Grammar", を is the particle to use when the receiver is also the direct object at the same time.
Key Examples they provide (they provide them for くれる and explain くださる as the polite (honorific) version of it - I modified them to use くださる instead of くれる below - I also highlighted how the receiver is handled in those two sentences):
A: 父は私にカメラを買ってくださった。(My father bought a camera for me.) Topic(は) Indirect Object(に) Direct Object(を)
B: 道男は私をなぐさめてくださった。(Michio consoled me.) Topic(は) Direct Object(を)
That said, the grammar point here only covers key sentence A in the construction notes, while also having an example fitting key sentence B - if I am not mistaken, of course :)
EDIT: fixed a typo in key sentence B where I had an extra う that didn't belong there