Depending on what your father likes, here's a list that I've come up with of what he might like (All of the following are from the 1950s and early 1960s, which I think is what you mean by 'older' and what I enjoy the most). If your father prefers a certain instrument, hopefully this list of each will help you:
Piano
Dave Brubeck: Time Out (Take Five alone makes this album worth it), Time Further Out, Jazz Goes to College
Ahmad Jamal: But Not For Me, Live at the Penthouse
Bill Evans: At Town Hall, Waltz for Debby
Oscar Peterson: Bursting out with the All-Star Big Band, At the Concertgebouw
Thelonious Monk: At Town Hall, Big Band and Quartet in Concert, Thelonious with John Coltrane
Vince Guaraldi: He did the Charlie Brown soundtracks (which are good), but his trio stuff is great. Jazz Impressions of Black Orpheus (Cast Your Fate to the Wind is the hit here), V.G. in Person, V.G. and Bola Sete: All Sides
McCoy Tyner: Inceptions
Sax
Gerry Mulligan (baritone sax): Concert Jazz Band at Village Vanguard, A Concert in Jazz, G.M. Meets Ben Webster
John Coltrane (soprano, alto): J.C. and Johnny Hartman (vocalist), My Favorite Things, Giant Steps, Blue Train
Cannonball Adderley (alto): Somethin' Else, Things are Getting Better, C.A. Quintet in San Francisco
Lee Konitz: Live at the Half-Note
Trumpet
Miles Davis: Cookin', Relaxin', Steamin', Workin' (all four are classics), Kind of Blue, Round About Midnight, Someday My Prince Will Come
Nat Adderley: Work Song
Dizzy Gillespie: Anything will do, but I highly recommend At Newport, Birk's Works, D.G. with Roy Eldridge
Art Farmer: Meet the Jazztet
Clifford Brown: C.B. Quartet in Paris, Jam Session
Trombone
J.J. Johnson: The Great Kai and J.J., Proof Positive, Dial J.J. 5
Bob Brookmeyer: Traditionalism Revisted
Arrangers
Gil Evans: Miles Ahead, Porgy & Bess, Sketches of Spain (those three are collaborations with Miles Davis and are must-haves), Gil Evans and Ten, Old Wine New Bottle (for what it's worth, Gil is my favorite). This is an excerpt of Miles Ahead:
Norman Granz: Any of his albums will do
Duke Ellington: Any are great, but if you do get one, get Ellington at Newport, his 1956 concert.
Count Basie: C.B. at Newport, 1959, C.B. and the Kansas City 7
Others
Modern Jazz Quartet: Django, Lonely Woman
Wes Montgomery (guitar): The Incredible Jazz Guitar of W.M.
Lionel Hampton: Hamp and Getz
All of the above I have on LP and am 99.9 percent sure are available on CD. Hope this helps.