Dr. Gerald Klooster, the Alzheimer's patient in Castro Valley who at one point allegedly was a prospective patient of suicide-doctor Jack Kevorkian, has died -- apparently of natural causes. He was 72.

In 1995 and '96, Klooster was at the center of a bitter family feud, custody battle and debate over the right to die that saw one son accuse his mother of planning a doctor-assisted suicide for her husband with help of the physician nicknamed ''Dr. Death.'' But a spokesman for the Alameda County Coroner's Office said there was nothing suspicious about Klooster's death Wednesday in a Castro Valley convalescent home.

''We haven't seen anything that would make us suspicious that the death was due to anything except natural causes,'' said coroner's spokesman Sgt. Mike Harper.

Harper said a the exact cause of death likely won't be determined until sometime today. Funeral arrangements haven't been announced.

Harper said that unless something crops up in a medical review or is requested by a family member, the coroner may not even perform an autopsy.

Klooster, a retired Kaiser gynecologist, had been placed in a convalescent hospital in March after he suffered a stroke while on vacation with his wife in Hawaii. For the past several years, he has suffered from advanced Alzheimer's.

''I feel a lot of grief now that my father has passed on,'' said Dr. Gerald ''Chip'' Klooster II from his Michigan office. ''He was a great man and I love him dearly, as I do the rest of my family in California.''

But since the highly publicized family warfare over his father, more than distance separates Chip Klooster and the rest of his family. Indeed, he has almost no relationship anymore with members of his immediate family.

Chip Klooster received the news about his father's death Thursday morning from a cousin in Michigan. One of his sisters-in-law left him a message Wednesday evening on his office answering machine.

''It's my understanding that my family in California have disowned me,'' Chip Klooster said.

Klooster family members in California could not be reached for comment.

Tragic disease

What by most accounts was a close-knit, deeply religious family was divided by Alzheimer's. Klooster was diagnosed with the disease in 1990. Three years later came the first serious manifestation, when Klooster became disoriented after leaving church in Danville and disappeared. He was found two days later, slumped over the steering wheel of his car in Aptos.

Ruth Klooster, his wife, confided to family members in September 1995 that the couple had joined the Hemlock Society and were collecting information on how to die.