Assalamu alaikum,
Please my question is, if one works, and time of prayer approaches, but the person is afraid of his or her boss to see him praying, may be for one or two reasons.Is he allowed to sit in order to hide and pray?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Standing while performing an obligatory prayer is one of the pillars of the prayer without which a person’s prayer becomes void except in case he/she is physically unable to stand. Since you are able to stand, then it is not permissible for you to perform the obligatory prayer while sitting. The fact that you do not wish that your boss sees you is not a valid reason for not standing in prayer. Allaah Says (what means): {Do you fear them? But Allaah has more right that you should fear Him, if you are [truly] believers.}[Quran 9:13]

Hence, if you want to perform the prayer while sitting so that your boss would not see you while performing Ruku’ or Sujood (prostration) because you are a woman, then non-Mahram men seeing a woman while she is performing the prayer is not a sound reason for her to abandon standing in prayer. For more benefit, please refer to Fataawa 89457 and 81837.

Allaah Knows best.