Shirley Ann Cosca

Shirley Cosca, a vivacious, vibrant, strong and fearless woman passed away peacefully in Sacramento, California, with all five of her children at her bedside on December 24, 2025, at the age of 91.

Shirley was born in 1934 in San Leandro, CA, to Isabel and Richard Boersig, the third of six sisters (Vivian (d), Joan (d), Claudia, Pat, Sue), and one brother (Mike).

Her father owned a steel business, but he was also an accomplished singer, performing light opera and singing in the church, and he encouraged Shirley to do the same. One of Shirley’s fondest memories was singing and even recording opera with her father as a young girl, and she had a passion for singing her entire life. Shirley also enjoyed the many experiences the Boersig family had while spending family vacations at their ranch in Sonoma County.

Shirley met Dennis Cosca at a dance during her senior year in high school, they fell in love and were married in 1955 after Dennis graduated from the Military Academy at West Point and remained devoted for 62 years. Their first few years brought them to Moore AFB in McCallen Texas, then subsequently to Mather AFB in Sacramento. In 1962, while Dennis pursued a dental degree at UCSF, Shirley navigated the bustling city of San Francisco with 5 small children in tow. All of this after having 5 kids in six years! Upon graduation, the family moved back to the Sacramento area, where they would settle down permanently.

Shirley was an exceptional homemaker and mother, who frequently advised her children “you can do anything you want if you really put your mind to it.” She had not finished college prior to marriage, but as her children went off to college, she too enrolled at Sacramento State and completed a BA in history. Shirley had a large, wonderful network of friends in Sacramento, and especially enjoyed her tight friend group, FTTS (from tennis to stocks).

Shirley and Dennis loved the outdoors, took their children on several strenuous multiday backpacking trips, camped regularly, took annual ski trips with their friends, loved to travel, play tennis and golf, and entertain at their home. Shirley had a quick wit and easily drew people into conversation. She loved to dance. She was also adventurous and decided to experience the thrill of skydiving with a friend to celebrate her 50th birthday.

Throughout her life, Shirley was genuinely interested in the lives of others and was always present for her family for the good times and a source of comfort and wisdom when needed. She often voiced encouragement by exclaiming, “way to go!” Shirley had a distinctive laugh and maintained that trait until her final days. Her family and friends will miss her.

Shirley was preceded in death by her husband Dennis. She is survived by her five children, Dave (Sue), Mike (Rosemary), Sandy, Cathy (Marvin), and Chris (Jenna), 13 grandchildren (Rachel, Scott, Matt, Stéphanie, Nicolas, Eric, Brian, Jackie, Gary, Stacey, Allison, Jessica, Jack), and 8 great-grandchildren (Michael, Charlotte, Teddy, Emerson, Arrow, Esme, Maya and Cal).

A private memorial service will be held to celebrate Shirley’s life. We’d like to offer a special thank you to the kind caregivers at Sunrise of Carmichael. In lieu of flowers, please consider a donation to organizations such as the Alzheimer's Association, or your local hospice provider.