I don't know the average height where he was, but 5'9 in most places is pretty good. I do not live in the states so forgive me for my ignorance.
He was attacked in school for his autism and shyness. That's why I suggested he could have started lifting weights and doing some combat sports. Elliot did *try* going to the gym, but foolishly trained everyday which means the muscles had no time to repair, thus not growing as a result. Nor did he eat enough.
He didn't live with parents, and his mental disorders could be fixed by going to the gym which would increase his neurological power due to the increase in testosterone. Before I began going to the gym I thought the ghost of Hitler was trying to communicate with me, once I started training that went away.
There's a difference between being incel and being too lazy to improve yourself. Blackops2cel is an example of an actual incel.