Steve didn't rush the other man. He was still uneasy but if this wasn't Loki than the way this man dressed and spoke meant he was most likely from far in the past and even Steve had been pretty shaken by the world when he woke up.
Once he got the answer though he put some water in the kettle, turned on the burner, and set it to boil, following exactly the way Peggy had taught him. While he waited he pulled out the tin of shortbread he pretended to not know the location of and set it on the table, sitting opposite Thomas. "Help yourself." He offered, leaving himself open to questions but not wanting to rush in to an information overload.