Internet recovery "An Error Occurred while preparing the installation"

So a friend felt his mac was becoming sluggish so decided to reinstall the OS on his 2016 MacBook Pro Retina w/ High Sierra. He started out by erasing in disk utility but then wasn't able to reinstall the OS. Since I used to work in laptop repair (not mac though) I've been trying to help him out.

Only way to boot it up is to internet recovery, choosing to reinstall the OS there gives the choice of 2x250gb drives, Untitled or Untitled2, whichever is selected the process starts and looks to work fine until what I'm assuming is the end, where it pops up with "An Error Occurred while preparing the installation"

I've verified the date in terminal and reset the NVRAM and still receive the same error.

From what I gathered google'ing this might have something to do with APFS. I've tried manually recreating the fusion drive following the instructions here: "An Error Occurred while preparing the installation. Try running this application again. Any OS.

But I can't erase the disk. Here is the diskutil output:

/dev/disk0 (internal):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme 251.0 GB disk0

1: EFI EFI 314.6 MB disk0s1

2: Apple_APFS Container disk2 250.7 GB disk0s2

/dev/disk2 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +250.7 GB disk2

Physical Store disk0s2

1: APFS Volume Untitled 5.0 GB disk2s1

2: APFS Volume Preboot 43.7 MB disk2s2

3: APFS Volume Recovery 1.0 GB disk2s3

4: APFS Volume VM 2.1 GB disk2s4

5: APFS Volume Untitled 2 5.2 GB disk2s5

I've also tried to make a USB bootable Sierra installer but I get a prohibited symbol when trying to boot off it. Even though it boots fine on my MacBook Air. The MBP had Sierra on it when it was new.