Can an unemployed stay at home mom be considered a teacher if she is doing at home distant learning? She is teaching them all day.

What are you trying to do?   If you are not actually employed as a K-12 teacher you cannot get the federal $250 educator credit.  There are no deductions on a federal return for home schooling, although there are a few states that have education credits for grades K-12.   

EDUCATION EXPENSES

Education expenses for grades K-12 are not deductible on your Federal return, whether for private, public, or home schooling, nor are the expenses for tutoring, after school lessons or after school activities, such as dance lessons, sports, etc.  Some states allow deductions/credits for K-12 education and/or home schooling expenses; if your state has these deductions available, you will be prompted to enter them when you prepare your state return.  (As far as I know, the states that offer any sort of K-12 deductions/credits are Arizona,  Illinois, Indiana, Iowa,Louisiana, Minnesota, and Wisconsin)