I disagree. They need to keep Mohinder around for 5 more episodes and devote 5 minutes of each of those episodes to different villains brutally torturing Mohinder, starting with Sylar. THEN during the 5th Nightmare man comes by and create an illusion of Mohinder's family.
Mohinder's father will berate Mohinder for crapping on his work, destroying his legacy, and for being a stupid stupid child who allowed Sylar become unstoppable while placing Molly's life in constant danger. Shanti will then reveal that she used to drop Mohinder on his head whenever she held him and that she used to put dung in his food when his mom wasn't looking. Mohinder's mom then will say that she never loved Mohinder and often found herself fighing the urge of drowning him in the bathtube or smothering him as she slept.
Broken and full of despair, Mohinder will do the honorable thing and go out Kurt Kobain style. With his rotting corpse on the floor, some random homeless man will break into the apartment, urinate on Surresh's corpse, steal his stuff then set the building on fire. The last we will see of Mohiner is his ashes being swept into a dumpster before being sent to some random landfill.