I 've been doing industrial maintenance for the past 40 years. I have an associates degree in electronics and completed a 4 year apprenticeship in electrical/electronic maintenance. I have a general class ham radio license. I hope to retire soon.
You have a bubble of air below the column of alcohol. You may have to start by putting the thermometer in the deep freezer in a vertical position or get some freeze spray to lower the column enough to get the air bubble on top. Try going through cycles of cooling and warming the thermometer and try to moving the bubble to the top always keeping the thermometer in a vertical position. If You manage to get most of the bubble towards the top then try warming the thermometer with a hair dryer. You should wear safety glasses when you do the next steps incase the thermometer ruptures. Position the thermometer so it is vertical. Using a hair dryer slowly heat the very bottom of the thermometer forcing bubbles to the very top. Then slowly let the thermometer cool and as the alcohol starts to drop it should stay in one solid column. Good luck.