The gift letter needs to state the relationship, the amount and that repayment is not expected, and the funds generally need to sit in your account for a period before closing so the lender can trace the source rather than seeing an unexplained deposit right before your purchase.
Gifted funds can cover the entire minimum down payment on an insured mortgage, 5 percent on the first $500,000 of the price and 10 percent above that, though some lenders still expect the buyer to demonstrate some funds of their own for closing costs.
Get the gift letter drafted correctly and the funds moved early, since a last-minute deposit is the most common reason a closing gets delayed. Get your hand-reviewed valuation from Joel Dyck.