I think you're totally in the clear to politely refuse to upgrade. I would explain to him that you looked into it, but you're afraid it just won't be possible. If need be (I wouldn't do so up front), you can outline the fact that it locks you into a contract for an additional year (will he pay to buy you out of the contract at your current ending date? If he did, would that be acceptable to you?*), and that there would be a penalty when you revert back to the regular plan (would he pay that penalty as well?*).
*These are provided as food for thought for you. Be prepared for him to offer to cover these expenses, whether his wife is on board or not - perhaps require her to sign off on the added expenses as well, and provide them with a tally of how much this will likely cost him by the end of football season (but with the disclaimer that it may not be all-inclusive, and that if there are any unforeseen expenses related to a temporary upgrading of service, they would be responsible for those as well.