What is the ruling if the bequest states the legatee can perform Hajj using whatever amount they wish on behalf of the deceased?

Primary text

If the testator permits the legatee to perform Hajj on their behalf using any sum they deem appropriate, the bequest is valid. The legatee is entitled to whatever amount they decide upon, unless the heirs do not approve, in which case the amount is limited to one-third (al-Thuluth) of the estate.