There is nothing wrong if one performs Hajj paid by someone else, whether the other person is one’s child, sibling, friend, etc. That does not affect the validity of one’s Hajj, because it is not one of the conditions of a valid Hajj that one should pay for the Hajj with one’s own money.

In this regard, the Standing Committee for Islamic Research and Ifta in Saudi Arabia issued the following fatwa: The validity of your Hajj is not affected by the fact that you have not spent any of your own money on it, or that you only spent a little and someone else paid most of the expenses of your Hajj.
therefore, if your Hajj fulfilled the conditions and you did all the essential parts of Hajj, then you have fulfilled the obligation of Hajj, even if someone else covered the expenses.