My most dear one,
You should recite OM MANI PADME HUM and the Medicine Buddha mantra loudly in your mother’s ear. Recite these mantras many times each day, also by chanting.
Strongly pray: “May she never be reborn in the lower realms forever, and may she be reborn in the pure realm of the Buddha where she can become enlightened, or receive a perfect human rebirth and meet Mahayana Dharma, and meet a perfect guru revealing the unmistaken path to buddhahood.”
Request the nuns at Chenrezig Institute to recite Amitayus Long Life Sutra forty times for your mother. Explain to them what happened, and that it is for her long life and for her to be healthy, so that her life can be highly beneficial for sentient beings.
Of course, they can dedicate for the long life of His Holiness the Dalai Lama and for all other holy beings in this world to benefit others; for all the Sangha who preserve the holy Dharma and spread to other sentient beings; for the benefactors of Sangha and the teachings; and for the many sentient beings who have a good heart and are helping so many other sentient beings. Also dedicate for the evil beings to meet Buddhadharma, to renounce the cause of suffering, nonvirtue, and to create the cause of happiness, virtue, and especially to generate bodhicitta. Dedicate to not harming others at all and only benefiting them, causing their happiness up to full enlightenment. Dedicate for all sentient beings,but do not forget the particular benefactor who you should pray for—your mother.
There is one more puja, she nyin dü dog, for your mother. That is to be done by the nuns at Khari Nunnery, which is down below Lawudo [in Solu Khumbu, Nepal]. Ven. Tendar can ask them whether they can do it and then you would have to make a money offering. If you can offer lunch or ice cream in place of a money offering, then I think it is good. Or you can offer around ten dollars, which is probably about ten rupees for each nun, for example. Or just offer them food.
If it is difficult for you to make this offering, I can make the offering for the Khari nuns. Thank you. Of course, I am making prayers.
With much love and prayers ...