Handling huge STL files

Hi guys, I’m at a loss here.

A client just sent me an STL file of one specific model for me to animate/ edit.

The thing has 40. million. polygons.

My computer (GeForce GTX 960, Intel core i5-4460, granted it isn’t the best) can barely open the file, let alone edit it. When I try to merge vertices by distance to lower polycount, blender shuts down

Does anyone have any tips on how to handle this? Maybe another program or something?
Asking the client to change it is not an option

What if you try to boolean half or more away. Then, in another copy boolean the inverse away to make the piece you try to work on fewer verts.

Meshlabs might be another option. Another free open source program. I’ve had good luck with it.

MESHLABS was the way to go! I thank you, Lord/Lady OLG, and award you 10 Internet Points for your cunning.

Boolean was also a great suggestion only blender couldn’t even handle that, I’m afraid.
Still, 5 Internet Points for your effort!