As long as you deposit it in the bank in increments less than $10,000 and in irregular amounts and periods, it will not attract the attention of Austrac - they monitor all three factors. E.g. it will attract their attention if you deposit $5,000 every fortnight for the next 20 weeks. This is due to the AML/CTF Act.
You can also receive gifts of up to $12,000 per year per person as well, according to the ATO. Just say your partner and you were gifted $24,000 ($12,000 each from the father before he died) - you do need to declare this on your tax return though. There's half your problem gone already....
PS this is not advice.