Please Help!

Ok, so I have a son that is 9 almost 10 year old son who currently weigh's 145 lbs, and I am very worried for his health. I have removed most of the junk food that is in my house, I keep fruits and vegetables and other healthy snacks that I can eat in the house for my kids to eat. I worry for my son because he is so over weight at a young age and I don't want him to grow up and have issues like I did with my weight. I want to help him now and that was one of the reasons I myself got healthy with my weight loss surgery. My son is a sports child, loves to play sports and his biggest sport is football which he plays from Aug. 1st through late November 4 - 5 days a week for 2 hour practice and then weekend games. While playing this sport he did loose the weight and has since gained it back, and now he is wrestling but it is only 1 day a week practice as he does it with our local boys and girls club. I need to help him now, and need all of your help to help me to help him. I am the only person in our house that works at the moment so money is in short supply, and I have looked into gyms and stuff like that where he could use equipment to help him with getting fit, and none of the local gyms will allow him to use any equipment even with a parent with him due to his age. I have checked the YMCA and they also won't allow him to use equipment with a parent. We also have a very small apartment with very little space to do exercising to videos (which I am working on moving rooms around to change this). We also live in New England and it is very cold here so to go for long walks at this time is very difficult with the weather. Most days we don't see temp's above 20 right now and so that is very hard to get motivated to go out and get exercise. I know my son likes snacks and he even will eat dinner and shortly after dinner he is hungry again. He will sneak food, and eat late at night when I tell him no more. I am looking for some ideas of ways to help him and snack ideas of ways to help him at this point. If anyone has any ideas to help me help my son, I would love to hear any and all suggestions! Thank you!!!