Finland did not receive any post-WWII (Marshall Plan) loans at all. Indeed, they 'opted out' and instead paid large sums to the USSR as 'reparations'. I did some searching and found that Finland received a US loan after WWI, though, and that that was repaid. I take it that your father referred to that loan.
FWIW, Germany did pay back the Marshall Plan loans. The last payment was made in 1971. (The largest recipients by far, btw, were the UK and France. I'll assume that those were repaid in time as well(?))
The Wikipedia article provides these and further details on the Marshall Plan.