His mom was in a deathbed for a good amount of time so he probably learned to play just to comfort her. That's not a stretch at all since he decided to become a merc to pay for her medical needs (attesting to how much his love is, for his mom). Piano is one of the least expensive forms of entertainment. His accent is a stretch for his character though.
Also, his mom was obsessed with Wesker. So she probably raised him up to be a smarty pants; and learning the piano at a young age is definitely on the agenda (just ask any parent with "high expectations" for their kid, I guarantee you they would have raised their kid on some form of instrument) --- REALDEMO
I guess "mysterious wanted men" in the RE universe have a talent for music or something. --- There is no such thing as a "Quick Time Event done right". A game that has Quick Time Events is a "video game done wrong".
What I can't understand is how the hell does he have a NY/Long Island accent?
Fun fact: Jakes Voice Actor was also Snows from Final Fantasy 13 and 13-2. --- Name: Light, FC for White version: 4084-2831-7220 FC for SS: 4685-6000-1404. Black 2: 4384-9935-2201 Name: Dark, FC for Black version: 2838-7396-7889