"They are a close-knit family with a special bond with their mom, who tied it all together," a source close to Depp tells WHO. "They took good care of her. She had been gravely ill for the last few years but they made sure she was well taken care of and had the best treatment. Johnny was very close to his mom."
Heard filed for divorce from Depp just three days after Palmer's death. They had been married for just 15 months, and the actress cited irreconcilable differences in court papers. She requested spousal support, which Depp has asked a judge to reject.
Meanwhile, the Heard source says "Amber is a family person" and enjoyed a friendly relationship with Depp's mom from the start.
"Amber was the one that suggested that they get married at Betty Sue's house," says the source, adding that she was also close to Depp's 14-year-old son. "She and Jack had a loving relationship."
In 2014, Depp was spotted taking Heard and Palmer out for a New Year's Eve dinner.
"It was obvious that Johnny was at dinner with his two favorite ladies," an observer at Ago Restaurant in West Hollywood told WHO at the time. "He seemed very, very happy."
• With reporting by ELIZABETH LEONARD