just taking a look at their site the menu at yoshi's, which is a jazz club with tons of history and respect and attracts the biggest jazz names, is more california or new american meets japanese... rather than strictly japanese food. for instance there was a short ribs entree. east meets west cuisine is often acceptable for many people, even those who balk at anything other than 'american' food, but what do i know, i grew up in calif.
if you don't want to go all the way to oak-town, you might try the latin jazz club in downtown san jose. run by pete escovedo. don't know what kind of food is there.
If you're in Los Gatos on April 13, 20, or 28, I'd like to invite you to stop by the restaurant "Viva" in the Cornerstone Shopping Center (next to Whole Foods) and let me and by band (The Trio Bravio) entertain you and your parents. We're a piano, bass, and drums trio, and play a variety of jazz standards, bossa novas, and blues. On Fridays we start at about 7pm and play til 11; on Saturdays we go from 6:30 to 10:30pm. There's no cover charge, and it's a nice little scene there, with good food, too.
Another option is to check the Jazz Datebook at kcsm.org, or listen to the listings on 91.1FM KCSM. Between us and the datebook, I'm sure you'll find something that will appeal to your father! And wherever you wind up, thank you for supporting live jazz!
My vote is for Yoshi's...I've been there many times and loved it everytime. However, if you are not in the mood to drive all the way to Oakland, try either Cetrella Bistro in Half Moon Bay. They have outstanding food, great ambiance, and live vocal jazz in their bar/lounge every Thurday thru Saturday. In San Jose, I recommend going to La Pastaia (at Hotel De Anza) for dinner (wonderul Italian cusine). Then having dessert and drinks in the Hedley Club Lounge (also in the hotel), while listening to live jazz. I think your parents might love that as well.