Yes I think if he installs the proper windows on his computer EU will work fine.
He has a proper Windows.
I suggest, go into BIOS, slam DELETE or F2 as soon as you turn on Power, to get in there.
Then Check if there is an option to prioritize the NVidia over the Igpu.
If the NVidia is prioritized, all games and software that use GPU will be using NVidia, and EU should run then.
And ofc don't forget to save when leaving the BIOS, if you made a change.
In case Igpu was prioritized before, well you will be in for a ride.
(Maybe you could tell what CPU is in there, as that is where the Igpu is on, if it's a intel)
It looks like the Igpu is not DX11 compatible, hence why it did run before on DX9.
And ofc assuming everything is up to date, Windows, GPU drivers, Intel drivers, blah blah.
Don't turn the Igpu off (in the BIOS) as you could use that to render video's with the proper software, in case you use that.
If this still isn't working after this was setup correctly, there is another thing that could cause this to happen, but i'm not even going to try to explain that here.
And normally I would suggest to update the BIOS also, but better stay away from it if you have no clue, as you could break the BIOS and basicly the motherboard would be scrap, if it went wrong.
In case this was mentioned before, sorry, I didn't read all posts.
And he even has DX12 on that GTX860m

If MA read this, maybe they could spread the load on the CPU a little better over the cores instead of relying mostly on single core.
(Which would ofc improve the smootness of the game alot, as there are sometimes spikes on that 1 core, And would result in a bottleneck, for sure on slower CPU's)
Not sure if that is possible with the old Cryengine, but imo it should be possible.