Is it permissible to combine and shorten the Maghrib and Isha prayers due to the nature of one's work? Is it valid to pray while sitting if there is an excuse? And what is the ruling on Tayammum due to the inability to maintain wudu?

The question contained three inquiries:

First: It is permissible for a working woman in a shop to combine the Maghrib and Isha prayers if she fears harm to her livelihood, her money, or the trust (amanah (definition)) she holds. This is according to the Hanbali school of thought.

Second: Standing is a pillar (rukn) in obligatory prayers. It is not permissible for a woman to pray sitting on a chair except in cases of inability. Her mentioned situation does not permit this. She must close the shop or a part of it for prayer. She must make up the prayers she performed sitting without a legitimate excuse.

Third: Tayammum (definition) (dry ablution) is not permissible except when water is unavailable or when there is fear of harm from using it. The inability to remain in a state of ablution does not permit tayammum. Prayer performed with tayammum in this situation is invalid and must be repeated. Water must be sought, even if by purchase, if the prayer time begins and it is not available. Jurists have permitted tayammum for one who fears the loss of valuable property if they leave to seek water for ablution. However, in this case, the property can be protected by closing the shop, so tayammum is not valid.