My father visited my uncle's grave this year, and accidentally killed one snake and the other ran away. My father is ill now.

Make a suggestion.

First of all, see a doctor, at least know what disease it is, have you received treatment?

Treatable treatment, I really don't think there is any way.

Ask a reputable gentleman, witch or something, and have a look.

Because of your grave digging, I don't know where you dig.

Is it when borrowing soil or adding soil?