K.G.
he will be fine with a loose blanket. He is old enough that when he gets hot he will kick it off. If hes sweeting he too warm. My dd runs warm all the time so she just goes to bed with a 2pc pj and her light receiving blanket or the blanket that my MIL made for her. its very light and airy. we keep our house at 73* and she has a fan that does not blow on her just to circulate the air/white noise. let him keep his security sack it wont hurt when you check on him before you go to bed feel him and adjust for his temp.