Bank deductions can leave the credited amount below the instructed gift. Confirm the US-dollar amount, the charging option and any intermediary deductions before sending. Ask the bank how the full instructed amount can reach the beneficiary, and retain the confirmation; a quoted debit from your Canadian account is not necessarily the amount received.
Currency, charges and what lands on the other side
Between a Canadian account and a US beneficiary, intermediary banks and conversion can both reduce the amount that lands. Ask your bank in writing for the expected credited amount and the charging option applied, and keep that confirmation with the file. Government, medical and professional costs sit outside the gift and the US$15,000 fee, and only that fee is described as non-refundable.
Ask your bank, in writing, three things: what the beneficiary will receive, which charging option applies, and whether any intermediary bank is expected in the chain. Then ask what evidence the bank can give you afterwards that the full instructed amount arrived. Conversion is a second exposure, since a rate quoted in the morning is not the rate applied at settlement unless the bank has committed to it, so ask whether it has.
Where a shortfall does occur, deal with it through the issuing channel rather than sending a second transfer on your own initiative, because an unexplained second payment is harder to reconcile than a shortfall someone has documented.