Should French Mastiff's Wear Jacket's?

Well,My dad has a French Mastiff but gave him to his friend.We couldn't keep him,and whenever he sees us (me,my 2 sisters and my dad) he jumps up on us and sits down next to us pushes his head into us..but i saw him this winter (probably 20 degrees-negative 1 degree) and he didn't do anything he jumped when he saw up but then he showed us his head and we pet it but then he went and turned away and just stood their,his tail is almost ALWAYS wagging but it wasn't..Was he cold? Should we get him a doggy jacket?