Your memory is right. The guitarist IS the grandson of Henry Kaiser. I think his father was HJK, Jr. who died early from Multiple Sclerosis. There are more entries on the Internet for the guitarist than for the Hurry-Up Henry who might well have been President if FDR hadn't been convinced to select someone else for VP, someone with some political experience in elected office.
The Kaiser Companies (there were 90 of them - Aluminum, Steel, Permanente Cement, Kaiser Sand and Gravel, Kaiser Electronics, Engineers, Permanente Metals, Kaiser Aviation, and on and on - with 100,000 employees on six continents) were sold because it became clear that the individual companies were worth a great deal more than the single entity.
Much of the money Kaiser amassed eventually went into charitable works not the least of which is the Kaiser Family Foundation which is independent from Kaiser Permanente but specializes in research on health care needs and the evaluation of health care technologies and delivery systems. The Foundation has a terrific record of achievement. The Rehabilitation Center that Kaiser set up when his son was diagnosed with MS is one of the best in the world. People come from Europe and Asia to study tecniques developed there even though there is a waiting list of several years to come study.
In general, the fortune started by HJK, including the millions from Fontana Steel, have been put to use for the general good. BTW, ten days from today, Dec. 31, will be the 57th anniversary of the opening of the Fontana Mill which began with the blowing in of Bess #1. (I don't know whether any industrialist ever named a blast furnace after his wife. He even had a quartette, the Harmonettes, I think, sing her favorite song, "Let Me Call You Sweetheart" at the ceremony.)