How far from retirement is your friend? 5-10 years, or 30+ years? A rough estimate is fine.
Is your friend in a stable job, or without work? That can impact their ability/desire to take risks.
Historically, a 3% mortgage is very, very low. There is a very high chance of beating 3% by investing - but investing is never a certainty. The longer the time frame, the more likely investing is better financially.
