When I looked for my used Honda CR-V I searched online sites like AutoTrader and looked at the CarFax reports for the vehicle having a complete history of having the oil changed EVERY TIME WHEN IT SHOULD HAVE BEEN. If it did not have that I did not even go to look at it. When I found my dealer Honda Certified the dealer had change the oil and filter, brake fluid, rear-end fluid, and put new brake pads on all 4 wheels, and 4 new tires that have the TPMSF rating before I even went to look at it, and I looked at it the day after the first day it was listed.
The dealer you are dealing with talked dealer certified, and did not even change the oil and filter, or even check the oil level and top it off. That is a BIG RED FLAG.
The previous owner put over 16,000 miles on one oil change and did not maintain full oil level. That is a BIG RED FLAG.
How many other times had the previous owner abused that engine like that, or even worse? It is a big unknown, and the fact that it was done once indicates that it was likely done many times.
Many engines do not properly lube the timing chain if the oil level is below the bottom mark on the dip stick, and if ran that way will result in the timing chain having to be replaced at much lower-than-normal miles. That is another BIG RED FLAG.
PASS, PASS, PASS. In other words, do not walk away from that dealer, RUN FOREST RUN.
Keep looking.