I had a similar experience with MH before. I booked SIN-KUL-NRT and the KUL-NRT leg was cancelled. There were no other MH flights that worked for me and several agents were only willing to offer a refund. After multiple calles, one agent was willing to escalate this and booked me on JL SIN-NRT direct.

I suggest OP's friend finds a OW flight and insists it. If the agent is not willing to help, HUCA.