It may have some dying capacitors in it. At your place, the mains A/C may be different enough from his (e.g. 122V for you, 110V for him) that it fails there first. You should indeed replace that PSU. A quality modern PSU has full range active PFC (no little voltage switch) and some level of 80+ certification for efficiency. Seasonic, Antec, Corsair, XFX, and Enermax/LEPA are among the better brands.
That is probably why it worked at my place and not at his. I have a PSU from my old computer that should work in his computer.