Doe Patronus Question

[sonjaaiston]

No: HPFGUIDX 174628

Regarding the doe patronus and the first time Harry saw it:

On Pgs. 366-367, it says "At last she came to a halt. She turned
her beautiful head toward him once more, and he broke into a run,
a question burning in him, but as he opened his lips to ask it,
she vanished."

I keep wondering what question is burning in him. IMO, it seems to
be more than just, "Who cast this patronus?" When I first read this
passage(before I knew it was Snape's,) I thought it seemed like he
knew something about this particular patronus and wanted to ask
something important. Is it possible he knew his mom's patronus
was a doe? Did he suspect some connection to his dad (doe/stag)?
Was there some other question instead? Or am I just reading too
much into it?

Sonja