The purpose is to make a huggable, lovable, childlike creature that is sadly dead.
It appears to be a hobbit, in a very odd death pose.
A medieval artist never thought of himself as interesting enough to express original thoughts. He humbly repeated what he learned from the elders. The results were majestic, although very often anatomically just as incorrect as this one.
Composition is an essential element of an artwork. Part of this persons problem is planning, it appears the plan was not made, many 2 minute chainsaw art contests place the subject better than this artist. The craftsmanship leaves a lot to be desired. I don't think he planned to make Christ look child-like. I think it turns out that way because he is sloppy.
I don't think anatomical correctness is the point, let me post some folk art while breaking a lot of rules is interesting and expressive.
How many Icons use duct tape?
I also found this charming Polish Folk art piece:
Both are horrible anatomically, but, are good composition wise, and appear some planning went into the work. The fingers in both these art works are also crude and stiff, but not wierd.
I think that Sommers' crudity is studied and affected. If you look at some other, secular art on his web page, it shows human forms that are very deliberate in their anatomy-defying weirdness.
I was going to look for some medieval crucifixes, but what you posted illustrate my point as well. The folk artists were not presumptious. There was no grand message that the esteemed artiste has for us. Their lack of skill is real. If they could make a finer sculpture they would. Not incidentally, the message in their case comes from Christ Himself, and it contains a mystery. Why is Christ surrounded by angels and saints? Why does he seem calm and unperturbed? The Paschal mystery is absent in Sommers' work, because he, of course, cannot comprehend it, and he refuses to be an instrument of grace, -- he wants to be the author of it. But what he does comprehend is huggability, cuteness, pity, -- things sufficient for exhibition art, pathetically shallow in church art.