Jim, I would extend to October and hope he can raise the funds. Technically he will default due to the penalty, however if he can pay slightly more than the tax interest and penalty so he is in a refund position, albeit small, then I fins the IRS often does not default the existing agreements. technically this is not the way it works, but mechanically I find the “refund” status avoids the default. Same for Offer candidates within the first 5 years after their Offer is accepted. Give it a try – there is nothing to lose.