I just tried to use this schmuck last night. I loaded the holotape into my pipboy, walked up to him and tried to send him to the Revere Satellite Array. He buzzed, whirred. Warned about Civilians. Responded like he got the command... and just stood there.
He did the same thing when I tried to activate him from the terminal in the junk yard.
Could've used his help too; at the level I am The Super Mutants there were a tough fight...
Robotics expert 3 lets you use him as a companion, but mortal, and not that strong by the time you get the perk,
I currently have him as a stationary "guard" outside covenant doing his voice lines and such, but he is too damaged to do anything useful anymore.
Can't you heal him with Stimpaks?
I mean, they work on Nick Valentine, so... ???
No, robots can't be healed,
synths, but not robots
The problem is the sentry bot never heals, and dies permanently, so I am using him as a statue.
Other hacked robots don't work as well because they are hostile to settlers, which means taking them to settlements gets them killed, but they are quite useful in combat.