Is it permissible to pay the debt amount to a paternal cousin who is ill with liver disease, and should the amount be paid as is, or is there an increase? And what is the interpretation of the livestock dying in the pen?

The amount you took from your aunt must be returned to her heirs after her death. You are not permitted to dispose of it yourself. The debt must be repaid in its exact amount, without increase, though an increase is a good deed. There is no evidence that jinn dislike the smell of livestock.