You need to sit down with him and set up some basic ground rules....
Has he set a timeframe for moving out?
Such as.... He needs to be the one at home taking care of his son... he shouldn't be gone 2 nights a week unless he takes his son with him (except for rare occasions.... there will be exceptions).
He needs to be the one responsible for taking care of his son... if he is home, he should be interacting with his son, not just zoning out in front of the TV, computer, game system, etc...... just as if he were in his own apartment. You aren't a live-in babysitter.
No cohabitating under your roof... your house, your rules!
I am assuming he is doing his own laundry, as well as his son's laundry?
Is he helping with household chores like dishes, cleaning up, lawn care, etc?
Is he helping out financially, like with groceries, or paying you rent?
Ground rules like this need to be set ahead of time....
Good luck......