Todd Fisher said there is currently no date and no confirmed location for the mother-daughter funeral, but plans are in process.
His "Star Wars" star sister died on Tuesday at the age of 60, days after she went into cardiac arrest while on an airplane. Then on Wednesday, Reynolds died following a stroke at the age of 84. Todd and Carrie Fisher were both born to Reynolds and her then-husband Eddie Fisher.
After Reynolds' death, Todd Fisher spoke to "Good Morning America," recalling his late mother "said she missed her daughter and wanted to see her again."
"I don't think she meant it quite like that but in 30 minutes she went to go see her again," he said. "I think she wanted to be with her. I'm not joking when I say she left to be with her and I'm happy about that. That's the only thing I'm happy about."
The two may have had a strained relationship at times, but they became extra close in recent years, even working on an HBO documentary "Bright Lights: Starring Carrie Fisher and Debbie Reynolds." It is slated to air next year.
They also lived next door to one another in California.
Todd Fisher spoke to ABC News separately about his sister's memorial prior to his mother's death, saying that Carrie Fisher's daughter, Billie Lourd, would be making the decision about what was to happen.
"Carrie loves a good party, so, you know, I'm sure she'll want to throw a party for her," he added.
ABC News' Sabina Ghebremedhin contributed to this report.