Can an employee call out sick for an indefinite time period?

I have a salaried (Exempt)co-worker who called out sick on a Wednesday. On Thursday he was a no call no show, on Friday he went to the hospital and was subsequently discharged that Sunday. Over the next 6 days after his discharge he was called over 100 times to find out his status. He texted a message to his supervisor on the 6th day that he was still sick maybe he might come in next week. It is now day 14 and we are still in the dark when this employee is coming back as we have had absolutely no communication other than his initial callout and 1 text message despite numerous attempts to his wife, house and his personal cell phone. Is it considered job abandonment since he has failed to call out each day?