Changing models joint constraint values through nodes?

So im in a situation where i need to have an character collapse (or “go limp” if you prefer in vr. Not the player.)
I had some serious trouble with collisions (vr hands go through the skeletal mesh when im not simulating physics no matter what i tried. The point is that when a character goes “limp”
it starts simulating physics and collides with that)

So i started to think what else could i use.
Is there a way to change the constraints in code so that when you start the game, the restraints are so stiff, the character stays upright but can be changed when “going limp” that it collapses.

Hopefully i was able to explain my problem well enough.