Sounds like the mail is being deleted from the server when downloaded on the computer. Sign into live mail, go to settings and set it to keep on the server instead of deleting. Than, he should be able to access from multiple clients or redownload if accidentally deleted from one. Also, you may want to go into the settings in whichever client he uses on the computer and set it to keep messages on the server.
Originally Posted by umang_k91
Sorry, I reread your initial post and see that it's a work account. You/he will have to go into settings on that account and change for not deleting. If you don't have the access to do so than he'll have to talk to someone at work who has the access. I'd imagine that the option should be available for you though, but each company has their own policies. And, as I mentioned above, clients tend to have their own settings for deleting on download or downloading a copy. If on webmail than the setting will have to be changed through the server policies.