Welcome to the community!
It depends on what type of TPG-NBN service is available in your area because every NBN Connection requires a specific modem / router as explained by @2fly below.
What kind of modem does your friend have?
But most likely yes you can use it.
FTTP requires a router only with no VLAN Tagging.
All tpg modem can be converted to router except for the Huawei HG659.
TPG will give you your own equiptment anyway.
If you're interested to get NBN service with us, I could arrange a call from one of our Sales Specialists to contact you and provide details.
... View more