Is it permissible for a Muslim to combine the Dhuhr and Asr prayers, either by performing the Asr prayer early with Dhuhr (taqdeem) or by delaying Dhuhr and performing it with Asr (ta'kheer)? And what is the ruling on praying while in the driver's seat or delaying the prayer until after its prescribed time, due to the unavailability of a place for ablution or prayer at his workplace?

A Muslim's most valuable asset is his religion, and it is not permissible to emigrate from Muslim countries to non-Muslim countries for someone who cannot observe religious rituals there. Being preoccupied with work is not an excuse for delaying prayer beyond its prescribed time. Your colleague must observe his prayers on time, either with ablution (wudu') or dry ablution (tayammum). Praying while seated in the vehicle is not valid if one is able to stand, and he must repeat the prayers he performed in that manner. Combining two prayers is permissible due to need and hardship, according to some scholars, such as the Hanbalis.