The second picture shows a very nice nebari and tapered trunk for the first few inches. I'm guessing this is why you got it. The first thing I would do is add soil to the container up to the level of the larger surface roots, so that the smaller ones don't dry out and die.
From there, I see two options, both of which lose the top of the tree. 1. Feed and water heavily and give it lots of sun, to see if you can get back-budding on the lower parts of the trunks/branches. 2. Or graft shimpaku onto the lower parts of the trunks/branches.