Patti, do you think 1776 would be suitable for a 13-year-old boy?
Yes, 1776 by David McCullough would be very suitable for a 13 year old.
The only off-color things I remember are the mention of prostitutes and an adulterous affair of one of the British generals. But there weren't any of the lascivious details you find in modern novels.
But I really don't remember the author using foul language. Although he mentioned it was used, he wasn't specific.
It is about war, and some of that is gritty. But boys that age should be learning about that sort of thing by 13, IMO.
We just sent it to my husband's grandson, who is reading at the 11th grade level, but is 11. And I also sent it to my cousin's son who is almost 11 and homeschooled.