but later on he called me sweating about that him accepting such request may put his computer in danger and scared that a virus can be downloaded or scared that it may give permission for a “virus” to access his computer details and files

No. Not at all what redistributables do.

would it be possible to add the current HDD as a 3rd one to the array, then convert it to a RAID 5 to prevent data loss?

No. That is not at all how RAID works.

Yes, you are just being paranoid.

Covenant Eyes is spyware and should be kept away from computers.

Seriously?

There are two screws on one end that you remove. That’s why it comes with a small screwdriver.