As far as I know (and according to the medical websites I checked just for this 😭), a deceased person's organs can be harvested for donation only if the person is kept on continuous ventilator support after brain death.
Tissues and corneas can be donated in other circumstances, but not organs.
In Samar's case, they brought the body home and only after Anupamaa's long monologue do they even decide to sign the organ donation form. A medical miracle made possible by the power of maa? 🪄