Move a calendar in Office 2011

Hi,
We've recently switched over to Office 365 and we have one user using Office 2011 on a Mac. I exported all of his old email, contact and calendar. I was able to import his old email and contact just fine, but his old calendar got put in it's own folder called 'On My Computer' I tried moving this folder to his Office 365 calendar folder, but when I search for the folder to move it to, nothing comes up. Also the option to copy that old calendar folder is greyed out. When I click on 'Import' and navigate to his .olm file it doesn't give me the option to import just his calendar, I wasn't sure if it would import everything again, giving him duplicate copies of his contacts and old email. Is there a way I can move his old calendar into his new Office 365 account? Any advice would be greatly appreciated, thanks.