No one can tell you whether the statement by your former tax advisor is accurate. No one outside the IRS knows what conditions can trigger an audit. It's a closely guarded secret. That also means that, unless the tax advisor who made that statement previously worked for the IRS, the tax advisor doesn't know what conditions can trigger an audit. You don't know what the source of the tax advisor's information was. Also, the IRS is continually refining its audit criteria, so what was true a few years ago might no longer be true.
One thing we do know is that Schedule A in your tax return shows only a single total amount for donations by cash, check, credit card, and other payment methods. So the IRS cannot tell from your tax return how much you donated in actual cash.
We also know that the IRS selects some tax returns for audit at random. There is no way to be absolutely sure that you won't be audited.
