What is the ruling on ridiculing others, and is the statement: "I can do your job while I'm asleep" considered ridiculing the person who devalues and scoffs? And how should one deal with such individuals?

Mocking people is forbidden, based on Allah’s saying: "O you who have believed, let not a people ridicule [another] people; perhaps they may be better than them." This indicates belittling and mocking people. When you are subjected to ridicule, it is preferable to be patient, to forgive, to turn away from them, and to seek refuge in Allah from their evil. It is permissible to retaliate in kind, commensurate with the offense, as long as it does not result in greater harm, based on Allah’s saying: "And the retribution for an evil deed is an evil one like it."