Refurbish clothes dryer motor by greasing the bearings?

I have Frigidaire fex831fs4 dryer for which electric motor appears to be seized: I am unable to easily spin the rotor with fingers (after removing it from the dryer) and the dryer makes humming noise while the start button is pressed, but nothing happens.

After some googling I found this youtube video where author appears to work on similar if not same motor and refurbished it by greasing the bearings: https://www.youtube.com/watch?v=UIi5RiRnaRI

Have three questions:

1. what is the black thing he is moving with finger at 0:45? Does it lock motor?
2. in my case the bearing cap does not want to come off easily after prying with screwdriver. Is it indicator that bearings are badly damaged or I did not try hard enough?
3. is it possible to replace only the bearings in case they are toasted?