It's hard to keep the thing from getting soggy. Rain sticks. Right now it has about 2 inches of stagnant water.
You can see my feeble attempt at plastic covering. And I had put rocks below the potting soil to try and keep it dry.
It sounds like bad - or at least ephemeral - design in the first place. If this thing is sitting there all the time absorbing rain, it's going to turn into a pile of dirt and rocks sooner or later.
Do people enjoy this object, spend time contemplating it in a thoughtful way? Or could it be an externalized tumor that has to do with some sort of family issue that no one is discussing?
You said it is a monster and may have had a statue of the Madonna. Is this object condensing fear or reverence for some overbearing maternal figure within this family?
Since this is in the dark, cold and shady side of the house, and has had no real application as garden it may be that there's something else going on.
Your idea of "knocking it down" is probably along the right path, but you used a destructive model of language and so of
course the family rejected it. If this "family heirloom" needs dismantling - or taming - as you said, you could trying changing your language to be more therapeutic and reverential. For example you could say that the stones are ill at ease in what is obviously an unpractical and awkward arrangement. You could sat that the stone could better serve the life of the house and the people if they could be transformed into light receiving, practical designs. This is basically suggesting the same idea, but it using positive, healing language. If the object does in fact represent a person, the "knocking down" suggestion would be akin to negating the person and destroying them with brute force. If you change to the language toward the side of "positive transformation", than the person this object represents can be helped out of the cold darkness and into a glorious situation of sun, light and life. The family will feel much more comfortable with the latter.
As your "monster" comment suggests, you're been called upon to
de something akin to exorcism. If that's the case, the family is looking to you to help them transform a tangle of memories, emotions and accumulated fears and repressions that this object may contain. Help them dismantle in a positive way it so that they (and you) can focus all this time and
energy on the sunny side of the house. Otherwise, this thing looks doomed to dissolve into a pile of mush. If it is merely bad design, without any of this other gobbledy-gook, you're not doing yourself any favors as a designer by trying thousands of tricks to make a bad design work. Be willing to walk away from it if they're not willing to take your honest recommendation as a designer.
Sorry if this is a little much, but honestly, that was my reading of the situation. In case you're wondering, this style of analysis comes from study of Alejandro Jodorowsky's "Psychomagic".
All the best,
Scott