What should I do about watching television and inappropriate channels, knowing that it is forbidden, and being unable to change my place of residence or prevent the existence of these channels?

Seek Allah’s help and supplicate to Him during times when prayers are answered, so that He may assist you in lowering your gaze and provide you with a dwelling and an environment conducive to adhering to the religion. Be diligent in performing prayers in the mosque and associating with righteous people there, and search for accommodation with upright individuals, far from corrupting visuals. Try to advise your colleague to desist from using media except for what pleases Allah, and treat him with kindness and good manners. Occupy your time with beneficial channels instead of corrupt ones.