If anyone can understand what Australia captain Pat Cummins is going through, it's Mitchell Starc.

Cummins will miss Australia's third Test against India, starting on Wednesday in Indore, after returning home to Sydney to be with his seriously ill mother Maria, who is in palliative care.

The star quick will be given as much time as he needs to be around his family, potentially also ruling him out of the fourth and final Test of the series.

During Australia's 2020-21 home summer, Starc was dealing with his father's declining health and trying to perform against a gritty Indian team.

He wanted details of his family situation to remain private during that series, even when he was coming under intense criticism for under-par performances.

Starc's father Paul died about a month after Australia lost the final Test of that classic series at the Gabba.

"Having been through a similar situation recently, it's a hard place to be trying to get your head around playing international cricket and for him to captain at the same time when you mind might be back home or with your family," Starc said in Indore on Monday.

"It's hard enough being in a COVID bubble in the same country, let alone being overseas and having to captain international cricket.

"Pat's a very resilient and strong character and I'm sure he was going through some stuff silently.

"He's exactly where he needs to be now to give his love and support to his family around him.

"I can only imagine that it would have been incredibly hard being over here with obviously a lot of noise back home."

Cummins, who was this week dethroned by star England veteran James Anderson as the world's No.1 ranked Test bowler, suffered some criticism for his bowling and captaincy during the first two matches.

The star quick also played a rash slog sweep to be bowled first ball during Australia's calamitous second innings collapse in Delhi.

It was only when Australia confirmed Cummins would not be playing in the third Test that he revealed the extent of his family situation.

Cummins' mother's plight has touched the cricket world, with the Barmy Army playing the song 'Maria' from the musical West Side Story in tribute during England's Test against New Zealand on Saturday.

"This is amazing @TheBarmyArmy, thankyou. Mum loved watching this and felt very touched," Cummins tweeted in response to the video.

Starc said the Australian squad were doing their best to support Cummins and his family from afar.

"We are sons, partners, fathers first, people first, and cricketers second," Starc said.

"He has the complete support of the group.

"It's been tough to see him go through it from afar, so nice for him to get the opportunity for him to go home and be around family to support the rest of his family and go through that not being overseas at the same time."