What kind of mental/spiritual therapy can someone in palliative care undergo?

Yoga meditation: Yoga meditation biofeedback type of treatments can be helpful.

Any kind: The best spiritual therapy is one that fits your values and beliefs and needs. What has helped you in the past (nature, music, art, prayer, meditation, anointing, etc.) and what has given you strength can best identify what you need. Spirituality means different things to different people and the strength one receives from it and the type of therapy is best defined by the patient that needs it.

Finding meaning: Such a person can work with a spiritually aware therapist who can help you find meaning in what's happening. As psychiatrist viktor frankl md said, “life is never made unbearable by circumstances, but only by lack of meaning and purpose.” finding meaning combats despair and brings peace -- even during painful times. It also affirms your connection with something larger than yourself.