It is understood that Amen, who is originally from Eritrea, lived with his father in Glasgow and had recently been granted 'right to remain' status in the UK.
His sister Delina Teklay, 17, said Amen had hopes of gaining UK citizenship and becoming either a basketball player, a doctor or an engineer.
She told BBC Scotland News that Amen was "not just my brother, he was my best friend".
She said he was a "really sweet person, so kind and so bright".
Amen attended St Thomas Aquinas secondary school in Jordanhill.
Headteacher Claire McInally said his death was a "shock to the school community".
Police Scotland launched a major investigation into Amen's murder.
Det Supt Cheryl Kelly said that "answers lie with the local community" and officers were reviewing CCTV and carrying out door-to-door inquiries.
She said: "Our thoughts are with Amen's family and friends at this distressing time. We will continue to provide specialist support for them."
The force has urged anyone with information to contact them via a major investigations public portal.
