yes it is possible that she might have episodes of TIA, and the thing is not all TIAs are noticable, some of which are just symptoms like headaches, dizziness and some mild pain that were usually just taken for granted. and since some TIA were unoticed, the next thing is already a stroke.
you can seek health or support groups for smokers.
your mom for sure already knows the effects of smoking to her body, but i think it wont hurt to remind her of it, that she is not getting any younger and even if she might state that she has lived her life for years of smoking, things aren't the same anymore, considering that she has had TIA recently.
sometimes, when they are made aware of the impending medical conditions, they start to think and realize that it is not just actually for thier own, but for the sake of those people around them that cares for them, especially thier families...