Hello Christine,
My daughter is 5 and she has T1D for 2 years now. She has a continuous glucose monitor (that brought back sleep for me) With the dexcom one of things that we found out is that in fact she does rise overnight. By midnight she is well into the 300s. But her lantus brings her back down so that does help. If the CGM is not an option, its ok to fingerstick as you and he feel is ok. I would talk to the DR about the sports. My daughter plays soccer too in the fall and it helps maintain her blood sugars without extra insulin. Before what we would do is check everytime when she came off the field, and she even signals her coach if she needs a break or something isnt right. You dont want him to give up the thing he loves. Just make sure to talk with the dr about the sports and even the coach and make sure to have low supplies on hand. They may even let you sit on the bench, to help monitor him. Eventually you will get like me (i have been diagnoised with anxiety issues) and have low blood sugar supplies hidden in every corner of the house.