That's a little too wishful of a statement, freedom is guaranteed of course, but there is no rule that free software will be more private just by virtue of having its code be open. For instance many free apps will still include analytics (proprietary or not), it's not the case with this one luckily
With free (freedom) apps you can always manually remove what you don't like. If the developer or company dies or loses interest you can take over development (or your friend can)