Dear Anno,
It is well understood that excuses do have limits and when it comes to work one should be serious about it.
Whatever measures our learned member have suggested are right and i would like to add up ;
The genuineness of the reasons needs to be checked.
Now, I will quote some examples which may or may not be related to your issue.
Some organization have strict rule for late incoming. If a person comes in late for more that 3 days his 1 day leave gets debited from leave account. So, bright employees of that organization start taking initial half days off. If they were about to get late for work after third late coming.
Do you have such policy in your organization.
In one more case, People who get boozed till late night shows incapacity in getting up early due to hangover.
As i said this may relate to your query or may not. but please do preliminary inquiry before sitting one to one with him for counseling.
Regards