My Dear Mike,
According to my divinations, it would be very good for you to perform Medicine Buddha practice for your grandmother. Visualize the seven Medicine Buddhas above her crown and follow the Medicine Buddha sadhana. Make very strong requests for her quick recovery, for her to immediately receive all the blessings, and for all her negative karma to be purified.

Then, as soon as death happens, pray for her to be reborn in a pure land where she can be enlightened, so that she may meet the Dharma and a perfectly qualified guru, and become enlightened.

You can also make this prayer after you recite each of the Medicine Buddhas’ mantra.

When you chant the last Medicine Buddha’s mantra, then do a strong visualization that nectar beams are emitted and completely purify all her disease, sickness, negative karma, and negative imprints. You can do this visualization again and again.

In one day do this practice five times. If you can’t do it this many times then do it as many times as you can.

Each time you recite the mantra do five malas with a good, strong visualization, especially visualizing the purification. If you can, visualize the seven Medicine Buddhas on the crown of her head, beams of nectar being emitted, purifying her, and you can also think that they purify you and all other sentient beings. You can think like this.

With much love and prayers...