According to the specs, it should be capable.
By using the Gigabit capable Passive Optical Network (GPON) technology, the HG8240 provides a high speed data channel through a single optical fiber with an upstream rate of 1.244 Gbit/s and a downstream rate of 2.488 Gbit/s. In this way, you can enjoy the high speed data service, quality voice service, superior video service
PDF Here: https://fccid.io/ANATEL/00521-11-03257/Manual-do-modelo-Echolife-HG8240/751FF67A-06D2-4A21-85C5-9875239A8A9E/PDF
They are testing on ethernet and not WiFi, correct?
suspect the issues is with your daughters equipment or testing method
what router is she using?
is it connected to the ONT via a gigabit connection? check the lights on both to determine this
is she testing via ethernet? and if so is it connected to the router on a gigabit connection?
how is she testing this?
the windows 10 speedtest.net has been shown to be one of the more accurate ones for testing as it rules out any browser issues.