Hi and welcome to the Chiari forum.
Ur guess is as good as mine, there is no real consistency with how Chiari is defined clinically....borderline many times may refer to how long the tonsils are, most Drs will not classify it Chiari unless the tonsils herniate more then 5mm's...but Chiari is not the herniated tonsils, it is the malformation of the skull which causes the tonsils to herniate...and regardless of how long they are u can have severe symptoms with what many refer to as mild...so none of the Drs terms fit how the patient is feeling. Another possibility for her symptom can be related conditions....could explain the asthma and other issues such as her vision....
What u need is a true Chiari specialist to do more testing...a CINE MRI which is a CSF flow study to see if she has an obstruction, then rule out by means of MRI's that she does not have a syrinx, disk, issues or tethered cord, so MRI's of the cervical, thoracic and lumbar spine are needed, and a sleep study to make sure she does not have sleep apnea...(especially since she has a DX'd breathing issue already) and ICP, POTS<and Ehlers-Danlos....
No way to know if her symptoms will remain as they are, Chiari symptoms can cycle, so she can go long or short periods without is, and long or short periods where symptoms flare....
Use the list of Drs in the Health Pages to research Drs...the list is not a referral nor an endorsement, it is just a tool to use to research Drs.....
http://www.medhelp.org/health_pages/list?cid=186
Many of us do need to travel to get to one of these Drs and it is well worth doing to get the best and proper care.