As he's, hopefully, a young blue you could give the rain a swerve and spend the day watching educational videos with him. I have also included some follow up consolidation activities to ensure a mixed curriculum.
Vid 1 - Luton 83 followed by some Art: make him draw a picture of man sticking his head out the window of a slow moving car
Vid 2 - Liverpool 96 - followed by some PE: ask him to put on a pair of casual 'slacks' and sprint down the side of the garden frantically trying to gain the attention of a (preferably ginger) family member
Vid 3 - QPR 98 - followed by some Maths/Physics: then get him to calculate the arc of the ball as it clears a floundering Martyn Walter
If you are feeling brave then move on to sexual health and relationships by getting him to recreate the sky sports news dildo incident using a suitable vegetable and another family member holding a hairbrush as a microphone.
Failing all of that is the football museum open today?