Vecchio: sostantivo o aggettivo?

The research which has been undertaken in psychogerontology and neuroscience has allowed to refute prejudicial opinions as regards the negative prospects of aging. There are active, enterprising and creative old people as well as others less fortunate, in situations of illness or disability.
The creative process, past experiences, the possibility of expressing oneself, and communicating with others, particularly younger people, to undertake voluntary service especially with less fortunate people of the same age and the use of ones resources and individual abilities allows many old people to strengthen and rediscover the “spiritual substance” and sense of self in terms of both their own identity and memories. Each individual person grows old in different ways, conforming to their biological, psychological, social and cultural factors. The aging process can be the complete realisation of ones life, and its meanings.
The old man, aware of his spiritual strength, of his dignity and his culture becomes the main character, the protagonist, the “substantive” of the human adventure.
The adjective elderly, which express time going by, is transformed - through experience, creative power, knowledge and self realisation - into its corresponding and far more dignified substantive “the elderly”.