Giving a sheep in sadaqah

Some days back I admitted my wife in a hospital because she was pregnant and doctors have confirmed that the child in her womb may have some defect and he may not survive longer. On hearing this news from the doctors, my mother decided to sacrifice a sheep in the path of Almighty Allah and distribute the meat to the neighbours so that Allah's blessings will be showered upon us. After the delivery, the infant was admitted in the hospital for 9 days and by the grace of Allah, the baby is recovering too fast and today we were discharged from the hospital. Now my mother is insisting to sacrifice the sheep and distribute it among our neighbours but I am trying to convince her that we should give the sheep or sell the sheep or pay its cost (cost of that sheep) to the masjid (mosque) which is under construction. Now I want to know what will be the better option, to sacrifice it and distribute it among the neighbours or to pay its cost to the masjid?