There are exemptions from the 60 day rollover deadline for certain situations, mostly custodian related errors, but no exception when you are using the money for such purposes. If the new home purchase fell through, you would have 120 days to return the funds to your IRA, but there is no exception due to complications and delays on the sale and closing of the former home. In fact, real estate transactions are notorious for delays and failure to meet the roll back deadline when IRA funds are being used as a temporary loan. Even if the old house was scheduled to close at the end of August, that would not alleviate the concern since many factors could delay that closing date.
Note that not being able to meet the deadline not only results in current year taxes, but also the loss of this tax deferred retirement plan balance from your IRA for future years. It might be worth it to look into a bridge loan from a bank that will allow you to meet the 60 day rollover deadline.
For your general info, the following explains the exemptions that are available for use to extend the 60 day deadline: https://www.irs.gov/pub/irs-drop/rp-16-47.pdf