They placed my mom on 10ltrs high flow

My mom was hospilized for COPD emphys with excerbation, chronic resp failure and high co2 hypercapnia. She had co2 of 92 upon admission. Abg was done and they placed her on bipap which helped her co2 lvl. Went down to 60. No confusion or fatique skin color rosy. they put her into a rehab no bipap and it shot up to 85 over a few days, back in the hosp bipap therapy 4 lts then to 3 lts of o2. She was doing wonderful for 2 wks. Back to rehab where they placed her on 10 ltrs high flow. She was good the first week and started to go down. Lethargic, confused, weak, daily headache. Her normal o2 saturation is ,92 they trying to get it to 99. They have had her on 10ltrs for 3 wks 24/7. Blood work was not done nor art. Bld gas. Is this normal? I feel it's making her worse. Rehab won't even give me the pulmonologist name or number. I am thinking of having her admitted to the hosp.again. from my knowledge 10ltrs makes co2 and is only used in a rescue situation her o2 sat has been 92 to 96 shouldn't they be lower the 10 ltrs or do it in spurts? Help! Dr is in Greece on vacation so I cannot contact him