A: Have you heard? Tom's mother died last night.
B: Poor Tom. He _________ feeling terrible. They were very close.
(must be / must have been)
My answer for this is: Poor Tom. He "must be" feeling terrible.
In my opinion, "must have been" shouldn't be used here because its tense is in Present Perfect Progressive and it can't be used with a sentence that has a time expression just like "last night."
But still, I am confused. Any help and opinions will be much appreciated. Thank you!