, or having a difficult time getting to sleep, is a very common problem. I would suggest you schedule an appointment for your father with a sleep medicine specialist
. It is great that your father is a non-smoker and a nondrinker as these two vices can cause problems with sleep. I don't think that vitamin B12 deficiency would likely be directly related to sleep problems
, but I suppose that it could in the context of the other problems that it can cause. Vitamin B12 deficiency can cause anemia and also can cause problems with balance. Often vitamin B12 deficiency is diagnosed after someone is found to have anemia and the vitamin B12 level is checked. vitamin B12 deficiency is often caused by a condition called atrophic gastritis which inhibits the absorption of vitamin B12 in the ileum. Very very rarely people become vitamin B12 deficient because of dietary issues, but this is not common.
Again, I would suggest you schedule an appointment for your father with a sleep medicine specialist. The sleep medicine specialist will likely want to conduct a sleep study on your father to determine the quality of his sleep and what changes could be made to improve his sleep. A sleep study can be very helpful in diagnosing the problem and coming up with the right treatment in the end. Good luck.