Hi, Paddon
Another suggestion: DirectTV (and probably most of its competitors in the cable/dish game) have a couple of dozen digital music channels. I've been pleasantly surprised that the "Blues" channel on our version of DirectTV has a broad playlist, ranging from Robert Johnson to Robert Cray and makes decent listening for those times I'm not able or inclined to tend the CD player or tape deck. Check it out if your Dad has access to DTV or similar. It'll not only provide him with a hands-free 24/7 playlist, but he can get info on the artists and tunes that really appeal to him right off the TV screen.
(How about that, 500 channels and there actually ,is something on!)
Best of luck - and by all means, encourage your father to check out the world of the blues in whatever fashion works for him!