The final match of the series will be played in Ahmedabad, starting March 9.
Cummins left the team after the second Test in Delhi and Smith took over in his absence, guiding his team to a memorable nine-wicket win in Indore.
Trailing 2-0 after humiliating defeats in the first two games, Smith led a brilliant Aussie turnaround in the third match also helping team qualify for the World Test Championship final in June.
A day after the emphatic win, coach Andrew McDonald shed light on Cummins availability, saying he still is back home but remained in touch with rest of the squad in India.
“He’s obviously dealing with what he’s dealing with at home but he’s still so invested in this group,” McDonald told reporters on Saturday.
“Our thoughts are still with him and his family at this difficult time.
“We’re in constant contact with him daily, so at the moment he’s not here and the test match is a few days away, so we’ll discuss with Pat on a daily basis.”
Smith led Australia between 2014 and 2018 before he was stripped off the honour following a ball-tampering scandal in South Africa.
He remains Cummins’s deputy since the paceman became test captain in November 2021 and has stepped in three times to lead Australia since then.
Smith said he had no ambition to return as full-time captain at any stage.
“My time is done. It’s Pat’s team now,” Smith said after inflicting on India what was only their third defeat on home soil in their last 46 tests dating back to 2012.
“I’ve obviously been able to stand in this week, obviously in tough circumstances with Patty going home. Our thoughts are still with him back home,” Smith said.
“But India is a part of the world I love captaining … it’s probably my favourite place in the world to captain.”
Smith marshalled his attack with aplomb, took a stunning catch at leg slip to remove Cheteshwar Pujara at a crucial juncture and overall looked in charge in the frenetic, low-scoring contest.
Former Australia opener Matthew Hayden was among those impressed by Smith’s “inspired” captaincy in Indore.
“You could tell that he was right in the match. He has been brilliant. Tactically on point, up for the challenge,” Hayden said during commentary.
(With inputs from Reuters)