The sacrament of anointing is the proper sacrament for those Christians whose health is seriously impaired by sickness or old age.
No, only priests may minister the anointing.
Developmentally disabled persons who lack the full use of reason can be anointed if they can be comforted by the sacrament.
The sacrament of anointing can be administered to those who have a serious mental illness and who can be comforted by the sacrament. Such cases should be handled on an individual basis and in consultation with the person’s physician.