You can also ask for assistance, sometimes called 'meet and greet' from Malaysian Airlines.
They can assist your mother from the plane and help her to get to the next connecting flight. Also if your mother needs any special assistance such as a wheelchair or help by using one of the buggies to get her around.
Just ask your travel agent if you booked through them or ring Malaysian Airlines direct and explain he situation and that your mum does not speak English. You will find the number on the Malaysian airlines website, see below. You can either ring the office in India or in Australia
If it was my parent this is what I would do. And it will ease your worry that your other is being looked after. Airlines do this all the time for passengers so its not unusual
You will not need to collect the baggage from KLIA as it will be routed all the way through to the final destination which is Brisbane. So checked it in in India, and pick it up in Brisbane, this is as she is travelling all the way through with Malaysian.
I dont know what terminal M is either but like maic suspect the same its the main terminal.
Need any more help just ask.