What is the ruling of Islamic law regarding a husband who delays prayer beyond its prescribed time, and sometimes combines them, under the pretext of differing times due to studying abroad?

Residing or studying abroad is not an excuse to delay prayer beyond its prescribed time. It is not permissible to delay Asr until sunset or Fajr until its time has expired. If the stay is for more than four days, it is obligatory to complete the prayer with four rak'ahs and to perform each prayer at its appointed time. Combining prayers is not permissible except for a legitimate Shar'i excuse, such as rain, illness, or an unusual necessity. It is advised to maintain prayers at their prescribed times and to gently and wisely counsel the husband if he is acting upon a fatwa (definition) that permits combining or shortening prayers.