What is the method of prayer and ablution for a nurse who is exposed to impurities in her work, and is she required to change her clothes for each prayer, and is it permissible for her to combine prayers during her break time?

The answer can be summarized in three points:

1. Purity of the body and clothes is a condition for the validity of prayer. Your mother can designate one garment for work and another for prayer, or simply wash the impure area.

2. It is permissible for a woman to wipe over her head covering (khimar) during ablution if it is wrapped under her chin and difficult to remove. This is the madhhab of Imam Ahmad and the fatwa of the Permanent Committee, especially in cases of hardship.

3. It is not permissible to delay prayer beyond its prescribed time except for a valid excuse. If performing the prayer at its due time is difficult due to work or study, it is permissible to combine two prayers (Dhuhr and Asr, Maghrib and Isha) either by performing them earlier (jama' taqdim) or later (jama' ta'kheer) to ease the burden and remove hardship.