You can take a process that grows out of a healthy culture and transplant it into a toxic one. Agile practices and pair programming cannot be divorced from the team culture. To do otherwise is cargo cult ritual management.

There is very little inherent to pair programming in itself that can be considered good or bad in isolation from the people using it. Good teams follow good practices. This is not because the practices are good, but because the team finds them to be temporarily useful to meet their specific needs.

If your manager went to a conference, learned about agile stuff, and returned to institute pair programming, you will likely find that to be of dubious value. If your team decides internally that the new hire should do pair programming with each of the existing team members until the greenness fades, that will probably have a better outcome.