Now if your beat down from lets say a 3,800 mile week then your FM should understand and let you shut down so you to catch back up. If you are only avg. 2500 a week then there should be NO reason you need more sleep. If its because you have not seen home then thats a different story. IMOP you should NEVER cry wolf on hours! that will only hurt you in the long run, but instead come right out and tell your FM that you have been out long enough its time to head the other way towards the house. Soon your Fm will understand how hard you run and when its time to get you home. Just be nice and start reminding him a week or so out when you want to be home.
If he's running 25 days and HASN'T run out of hours, obviously he's not running hard. He's picking up hours daily, so dispatch is running him. If he's new to the biz, well, this is trucking. He should put in for time off. How many miles is he running weekly ?