How and how long to get ITIN of foreigner?

Sorry, my PC doesn't have Chinese.

My sister sold house and should close on May 4th. then May 1st, we knew buyers need to holding tax money 15% for IRS.

my sister is Chinese citizenship and doesn't have ITIN. Escrow agent told me to get ITIN.

I asked ITIN agent today and he said it needs 2 or 3 months.

Is there an anyway to get ITIN soon?

otherwise, is there a way to let IRS to hold money without ITIN?

thanks a lot for any help!