I don't understand why you advise her to purchase a VPN, while she found a way to avoid using one in her country.

AFAIK her country, cmiiw Indonesia, doesn't belong to the list of countries banned by sportsbet ToS. Then she doesn't need to hide her IP, she won't face any problem from sportsbet IMO.
I'm speechless. Do you really think that changing DNS servers is a better solution when compared to paid VPNs like Nord, Express etc? If that was truly the case, these paid VPN services would have shut shop long back. Think!
Also, she might not face any issues from Sportsbet(Customer care needs to clarify that), but she could definitely face issues from her government later on.