Sleeping between 10 to 12 hours is very normal for some people depending on how tired the person is and how many hours the person works per day.
Some people just need more sleep than others. I sure wish I could get 12 hours of sleep because I really need it but I cannot sleep in any later in the day due to having to be up at 6:00 AM to get to work and I cannot go to sleep earlier in the day when I get home from work.