My most dear, most kind, most precious, wish-fulfilling one, 
As well as Medicine Buddha puja, also liberate one hundred animals. They can be insects that would otherwise be killed, for example, eaten by another. So liberate about one hundred animals for his long life according to my advice on how to do animal liberation. This includes going around holy objects, sprinkling blessed water on the animals and so forth.

I will read the Diamond Cutter Sutra for your father and also do a puja called chag sum.

The puja she nyin dü dog needs to be done by Samtenling, the Gelugpa monastery near Boudha Stupa.

The best puja for your father to recite is this:

By my experiencing this sickness or cancer, may all sentient beings be totally free right now from disease, spirit harm, negative karma and defilements.

Your father should keep on reciting like that, just as Tibetan people recite OM MANI PADME HUM, like on a mala. That is the best practice, the best purification, the most powerful way to collect merit and the quick way to achieve enlightenment.

With much love and prayers ...