Although the grandmother's ancestral laws are strict,
she cannot go after the decaying husband under the constraints of Chrono-Law if he keeps avoiding Winter Duchy.
And the decaying husband even timidly hid underground, not daring to take even that risk.
But in reality, even if he were above ground, the grandmother could not easily lay a hand on him.
Because, if the grandmother actively violated Chrono-Law, she would have to pay a considerable price—even if it could be repaired through rituals, it means for a period of time she would be stripped of her immortality, and her own power would be suppressed by the Divine Power left in the Chrono-Law ritual by other True Gods.
The duration of this deprivation is determined by the time taken by the grandmother to act.
Even if the grandmother could wipe out the decaying husband in an instant, she would still be sealed for about half a year.
If it were usual times, it would be nothing.
Just a matter of dozing off and it's over.