Why do people with brain injuries sleep more?

Brain controls: Sleep regulation is highly complex and involves multiple areas of the brain. With brain injury there could be increased, decreased, or irregular sleep due to imbalance between brain chemicals. Depression might cause increased sleep. Certain medications administered can also cause sleepiness.

Well I think: They are more somnolent because they have an altered sense of awareness and sometimes they even do not respond to noxious stimuli if they are very somnolent. It is usually dependent on the amount of injury. You should ask your doctors about this. Level of consciousness is very important to follow when you have a brain damaged patient.