My father wanted to donate his body to a medical college. Is that against dharma?

no — it is a gift for others' good; honour the wish and do the rites with a symbolic body.

Hindu tradition honours self-giving. The story of sage Dadhīci, who gave his bones so the gods could make the vajra, is often recalled for exactly this reason. A body that helps doctors learn to heal is a lasting dāna, and many religious teachers today speak in support of it.

When the body goes to a medical college there is no cremation, so families do the rites in another way. Commonly, the family prays with the body before handing it over, and the priest then performs the rites using a small effigy of kuśa grass or palāśa twigs in place of the body, sometimes with a symbolic fire. The 10th, 12th and 13th day rites and the annual śrāddha are done as usual.

Respecting a parent's final wish is itself an act of dharma. Keep the donation papers and talk to your priest early so the rites can be planned calmly.

Source: Dadhīci story (Purāṇas); common practice of effigy rites

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