My Son Refusing to Sleep...

Okay it's could be a culmination of things: dad gone, not tired etc.
I would switch off tv 1/2 before bedtime, lie in his room w/dim light and read a book in bed.
Do you have a bedtime routine (ex. bath, pjs, story time etc.)?
Stay with in his room for a few mins.
Make sure he's really active during the day: running, jumping playing, park, go for a walk, have him walk everywhere: inside the stores etc., have him help you wash your car.

I would turn the tv off, dim the lights, have down time. It's hard to say since I don't know your son's age range.

When my husband was a kid, if he wasn't sleeping, his mom handing him a bucket of warm, soapy water, a rag, and made him wipe down walls. That made him sleepy real fast!

probably a combination of things. I do not let my kids watch tv before bed, I think it is too stimulating I let them read books or read to them instead.
A warm bath helps calm them down, especially if you use some soothing bath wash ( all my kids have always been fans of baths) there is a lavender and chamomile bath that is good for night time. Also when my middle child cannot sleep I make her warm milk or hot chocolate and it helps her sleep. There is not enough positive things I can say about having a good bedtime routine, it really puts kids in the right frame of mind for getting their mind and body ready for sleep.
I am a big softy...I would probably either suggest laying down with him, or I have always let my kids get in bed with me...you just have to be careful because it can become a habit easily. Good luck!

Turn off the TV an hour before bed. Lots of research on the benefits of this.

My eight year old often has trouble sleeping. We use melatonin to help him.

He has to lay quietly in his bed for 45 minutes. If he still hasn't fallen asleep, he gets a small dose of melatonin, which consistently knocks him out within 20 minutes. Usually, the knowledge that he *can* get melatonin is enough to calm him and he falls asleep on his own within 45 minutes. On the rare days he's truly insomniac boy, the melatonin is a promise that he won't have to spend hours trying to sleep.

Did his father tell him where he was going and when he would return. Kids worry. When your husband calls tell him the situation and have him talk to your son.
I had the same problem with my daughter when her Dad had a Monday night class and did not come home before she went to sleep.
One Monday night I asked him if he'd told her where he went. He said she knew and I asked him if he'd told her. In the morning he did and we had no more Monday night bedtime problems for the rest of the semester.

I would try sticking to a strick tv time and stick with it, if he gets up and turns it on or something take it away from him.