It is not always possible to fulfill the usual rules; one must take circumstances into account and try to fulfill what they make possible, as far as one can. The demons themselves are not unmindful of this law. So, being in constant enmity with us, they prevent us from doing what is possible and urge us to do what is impossible.
Let us look after those who precede us into the other world, and do for them all that we can, remembering that Blessed are the merciful, for they shall obtain mercy.