Very belated reply, but the board is dull at the moment so I'll offer my advice.

1) Movement. He can't hit what's noit in range. Practise is the only way to improve movement. This can also help in getting him fatigued.

2) Defence. When fighting a fellow who swings crazily, often the best defence to adopt is the hands up style as slipping and bobbing can get you caught. (Often a wild fighter can catch a guy good on the defence like that)

3) Straights. When the hands are up on the inside use straight punches. It's easy tire a wild guy and straight opunches will penetrate whatever guard he has.

4) Step in to him. Seeemingly contracdicting the movement theory, I find oftemn a wild punchers worst are is close to him. They will be accustomed to people moving to avoid their swings and therefore will not be affective close in. Sharp uppercuts close in do the job.