But we have a new employee that would rather all his email in one inbox. I know he can forward the mail to his personal account, send mail using an alias so that it looks like it is coming from the company account, and that a simple bcc could put a copy of any replies back into his work account, but I feel like I should have some privacy concerns with this. Any input would be great!
The user sounds like the person who has a privacy concern, since a significant side effect of that action is that the company is prevented from access or control over his email account.
The company has operational concerns, as the email can't be recovered easily in the event of the employees resignation or incapacitation. The company does not really have a privacy concern, since even if there was no off-site forwarding, the user can still easily reveal email contents.
This is a management problem, not an IT problem. If your company policy forbids sending work email outside company control, then enforce the policy. If the policy does not cover that scenario, then is there really a problem? (If it is a problem, then write some policy!)
You should really use your own domain name, which is the same as business name. You can then use Google Mail to actually use it. On your website, you say stricte, that only authorized mail comes from the company domain name and not any other. Anyone can copy email, but you can have control over your domain name, regardless you keep using gmail.