Dymock, who is a former assistant and short-term coach of the Canterbury Bulldogs as well as former Tongan head coach and Australian representative as a player, has been serving as Holbrook's assistant coach throughout the season.
The club confirmed on Monday in a short statement that Dymock has now finished with the club.
"We thank Jim for his time on the Coast and wish him and his family well in the future."
While that in itself could trigger rumours he is on his way back to Canterbury in some shape or form, with the Bulldogs also looking for a new head coach for 2023 and beyond, Dymock's exit has more immediate ramifications for Holbrook, who, one by one, is losing his staff.
The decision for Dymock to end his time at the club follows a reported decision just weeks ago for high-performance boss Klint Hoare to step down.
The Titans' form has been nothing short of shambolic this year, and only for and against is keeping them out of last place on the competition table as it currently stands.
It was reported after their most recent loss in Round 16 that the Titans would use the bye week to replace Holbrook, however with no move yet made by the club, he now appears safe for at least the next week.
Time to turn things around is fast running out though for a club who could well become impatient at the slide down the ladder.
Despite that, just a month ago Holbrook said he wasn't feeling worried about the status of his employment with the club.
"I'm not (worried about my own job), I'm disappointed about how we are going," he said at the time.
"I feel horrible; we're letting a lot of people down.
"There's been a few other coaches who have unfortunately been moved on but I feel very privileged and lucky that we have had a conversation around where we've gone.
"Since I came in, we went from last to ninth and then ninth to eighth and you naturally just want to get better. I feel secure in what I'm doing."
Things aren't about to get any easier for the Titans either, with a clash against the Broncos coming up this weekend.