By overstay, do you mean na 7 years syang nasa Australia na walang valid na visa? Pag walang valid visa the person is considered an unlawful non-citizen and will be detained and deported kapag nahuli. Since balak naman ng Tito mo na umalis ng Australia, I don't think haharangin pa sya ng immigration pauwi. However, may possibility na mabigyan sya ng ban and hindi sya makabalik dito agad and it may also affect his chances of being granted a visa in the future.
Yung Tita ng kaibigan ko nag-overstay din pero kasi nagkasakit at na-ospital for over a month kaya hindi nakaalis bago mag-expire ang visa. Nakabalik naman sya sa PH nung nadischarge na sa ospital.
Ang pinakamabuting gawin siguro ay magconsult kayo ng immigration lawyer para mas ma-guide kayo based on the reasons kung bakit naging ganyan yung situation ng Tito mo.