Too old for piano lessons?

Is there an age limit for learning how to play the piano? I really don’t know how to react when my 70-something dad indicated his interest in taking piano lessons. He plays the keyboards by ear, but he has long ago expressed interest in learning how to read notes. He would always drop by the Casio music store when we visit SM, admiring the musical instruments on display and observing the pianist playing some popular tunes.

I think Dad prefers owning a keyboard or synthesizer than a grand piano. But I’m pretty sure he wouldn’t mind having a portable digital piano just like the px130 which sounds like a real piano without being too bulky. One time, we visited a music store and one of the staff offered to teach him home piano lessons by the hour. I’m just wondering though if his enthusiasm for playing the keyboards provide the passion and energy for actually undergoing what is required to complete even a basic piano course?