That's why I suggested he ask her outright, Cain.
But, unless she's just using him for the reasons I said, its likely she does like him, else she wouldn't go to the effort to take him out for his b-day & text him. I've had lots of men hit on me even as a married woman over the years. Except for one very unusual exception (a male family friend we've known for 20 years), I don't respond to any of their obvious advances. Its just too much hassle.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh