on 13 DEC 2016 he found a transfer of 49.5. btc was sent from his account to
If he didn't initiate any send action there, I don't see how it could be a glitch in Mycelium.
Unfortunately, from what I read, my conclusion is that somebody else got access to the private key of 13uzBESjqTT87ak4uAipKUoP8EuVHcQk2e and stole the coins by sending them to 1EF3DDBaPzbpJ5cXHVW2gZkyG1Jd4FotFW.