Thanks for that, this is very interesting. Here is a fuller quote from that source:
RUTHERFORD ESTATE ET AL v. CITY OF SAN DIEGO ET AL. Joseph Franklin Rutherford finally succombed to a long battle with rectal cancer on January 8, 1942. Even in death, Judge Rutherford managed one last attempt to bully non-JWs and the government. In all likelihood, Judge Rutherford intentionally set the stage for his final legal battle. Rutherford was an experienced attorney who started his career as a small town Missouri lawyer handling routine small town matters, and wound up his career handling cases involving interpretations of the U.S. Constitution before the Supreme Court of the United States. Thus, there was no reason why Rutherford should have specified that his corpse be buried at a location which was not approved for burials, unless Rutherford wanted to be certain that his demise would be celebrated in a courtroom.
Judge Rutherford died at his 100 acre southern California estate located in the hills outside San Diego. The 5100 square foot mansion, named "Beth-Sarim", or, "House of Princes", had been built for Rutherford by some of his wealthy followers, in the late 1920s, after he was no longer welcome at the home of his wife, Mary Malcolm Rutherford, in Monrovia, California (north of Los Angeles). Rutherford had purchased the Monrovia home around 1915, when he had moved to California to see after the WatchTower Society's west coast operations. After Rutherford became President of the WatchTower Society, he spent time in Monrovia whenever he traveled to the west coast on WatchTower business. However, by the late 1920s, Rutherford apparently had become completely estranged from his wife, and even his only child, Malcolm Rutherford (born 1892), who lived not far from his mother. Malcolm Rutherford had been a "Bethelite", who prior to Rutherford becoming President of the WatchTower Society, had worked intimately with both his father and Charles Taze Russell in WatchTower activities.
If what this says is accurate, then it would imply that the move to Monrovia had nothing to do with the Pottenger Sanatorium. But there are some big problems here that make me suspect that the source has confused two separate residences. As one can see in my data dump on the previous page, Mary Rutherford did not live in Monrovia (at 160 N. Primrose Avenue, Monrovia, Los Angeles, California) in 1920; she lived at 128 N. Eastlake Avenue, Los Angeles, California. And it is at this address where Malcolm "lived not far from his mother," as Malcolm's address in 1920 was 124 N. Eastlake Avenue, Los Angeles, California. The Eastlake Avenue address is found in Malcolm's 1917 draft card, the 1920 census, and the California Voter Registration Index for 1924 and 1926. It was then that Malcolm moved, not to Monrovia, but to 6246 Drexel Avenue, Los Angeles, California, as stated in the 1928 index and the 1930 census. Later Malcolm moved again, to 2207 Laverna Avenue, Los Angeles, California (whereas he was living in Arcadia, California decades later when he died). There is no indication that Malcolm had a separate home in Monrovia. Mary, meanwhile, had her home on Eastlake Avenue in Los Angeles before moving to Monrovia. Since Malcolm was living on Eastlake Avenue as early as 1917, this suggests that it was the Eastlake home that was purchased in 1915, not the Primrose one in Monrovia.
Then later Mary's address was given as 159 Stedman Place, Monrovia, California. This is actually an adjoining property to the Primrose home and according to VM44 the house there was built in 1935. It is possible that Malcolm moved there next to his mom at that time in the mid-1930s, and that is what the source means by saying that Malcolm "lived not far from his mother". But this is already a time far removed from the situation in the mid-1910s, where Malcolm lived near his mom in Los Angeles, and the late 1920s when Malcolm lived in Los Angeles and Mary lived in Monrovia (the Primrose home is located 12.8 miles away from the Eastlake address where Malcolm lived before c. 1928 and 25.8 miles away from the Drexel Avenue home where Malcolm lived from 1928 onward).