Is Lupin James?

[mumweasley7]

No: HPFGUIDX 109656

 In Book 3 Prisoner of Azkaban: Shrieking Shack  
Lupin was lowering his wand, gazing fixedly at Black.  The professor 
walked to Black's side, seized his hand, pulled him to his feet so 
Crookshanks fell to the floor, and embraced Black like a brother.
Notice 'gazing fixedly' - really looking him over. And embraced Black 
like a brother.

In Book 5 OOtP, Sirius is explaining his family to Harry when he says 
he went to live with James' family after his family rejected him and 
they treated him like their own son.

Is the reason Lupin doesn't touch Harry simply because he's so 
overcome with emotion that he can't afford to give away his secret 
and therefore chooses not embrace his son, and also why he shivers to 
hear Harry talk about his mother's screams?

MumWeasley7