My 86 yr old mom has COPD. I took her O2 level and it's 70. I know that is really low. Can she wait 15 hrs to call a doc?

Her primary doc could not get a level at his office 2 wks ago. His finger ox deal must have needed a new battery or whatever. Called 2 days later & told her to go to the hospital to have it taken. Couldn't because of money issues. She has been like this for weeks, very fatigued, wheezing, out of breath with the slightest movement. She has 3 different inhalers she now uses. She also has many gut issues...acid reflux (severe) diverticulitis and is on medication for that. I am sure she is anemic as well. She only weighs 90 lbs, but is probably only 4'.