They are very brittle because the plant has been feeding off of the leaves for weeks, instead of feeding off of the soil (due to nutrient lock out).. It will continue to so until you chop the plant. I wouldn't remove them at this point. Just let them fall off. I'm sure they are the only source of nutrients at this point so might as well let the plant use every last bit of what the leaves have let. From what I read, the issue was most likely caused by the Dr earth top dress.. That's some tricky stuff if you don't have a grasp on how nutrients work.. and the instructions do not have auto flower cannabis in mind, which ends up being way too much for an auto flower.
The thing about deficient leaves/plants is that the quality of the bud will be severely effected. I will not taste, smell, smoke as well as it should/could. Same goes for the trim from sick plants.. It doesn't wash/make hash nearly as well as it could. Next time you'll want to address those issues as soon as they start. You'll definitely get to harvest.. Next run will be better Im sure!