Information on the best vow/Baare to do for a child's health and safety

I am a Sri Lankan Buddhist looking for help .. Our child is very sick and doctors have said any help is difficult to be given at this time for her or operated on. I would like to ask for information on the best vow/Baare to do for a child's future health and safety and to cure any problems, which deities would be best to ask for protection or some ritual that is undertaken to be continued for her safety and things like that? (at the Temple of the Tooth relic preferably as we will be visiting this month).. Any help is gratefully accepted.