Is it permissible to substitute a lamb vowed as a sacrifice with a calf, intending thereby to fulfill the vow and give charity on behalf of the deceased father?

If someone vowed to sacrifice a sheep for the healing of his child, and his child was healed, then he is obligated to fulfill his vow. It is permissible to sacrifice a calf instead of a sheep, provided that the vower's share in the calf is more than one-seventh of its value, or that the meat of one-seventh of the calf is more plentiful or better in quality than the meat of a sheep in his locality, and that the intention of each participant in the calf is separate. The evidence for this permissibility is that sharing with more than one-seventh is better than a sheep, and that the Prophet, peace and blessings be upon him, permitted converting a vow to something better. However, if the vower's share is only one-seventh of the calf's value, and its meat is not more plentiful or better in quality, then he must sacrifice the sheep to fulfill his vow.