premkumar wrote:What spiritual advice can we give to him?
To paraphrase Pink Panther's response to another recent topic ...
Don't get involved with the Brahma Kumaris because all they will do is take the family house and money off him.
The honest answer is, that is just what happens as one gets older. There are no magic wands, don't waste your time, money and energy seeking magical cures.
Brahma Kumarism produces marketing material like BK Shivani's programme, to attract vulnerable and needy people ... and them exploits them or their families. They do not have the answers you seek. It's just marketing for an entirely different purpose or product.
The Brahma Kumaris are an End of the World cult. End of the World cults are a *very* bad idea to introduce depressive individuals too, unless you want to end their lives quickly. If you are happy to end your Father's live quickly, then by all means pack him off to Mount Abu ... just make sure he signs over all the family's land and property to the family estate otherwise the BKs will get it.
Good luck.