Is a Muslim required to remember Allah, invoke blessings upon the Prophet, and recite specific supplications before every action, even if it is a simple one, and would a single supplication at the beginning of the day suffice instead of repeating the remembrances for each action?

The remembrances (adhkar) of day and night are recommended, not obligatory, although some scholars have deemed it obligatory to say "Bismillah" (in the name of Allah) before eating and drinking. The Basmalah (saying "Bismillah al-Rahman al-Rahim") is not prescribed for every action; rather, it is recommended for some actions, disliked for others, and forbidden for still others. Mentioning the remembrance upon leaving and entering the home is a recommended Sunnah. What your friend does by frequently engaging in remembrance is praiseworthy, and there is no hardship in the daily and nightly remembrances, as they are short and mostly recited verbally. Any difficulty he experiences might be due to reciting long supplications not authentically reported in the Sunnah, or he might be afflicted with obsessive doubts (waswasah) regarding the pronunciation of the remembrances. What is important is that remembering Allah the Almighty is sought after, and the greatest way to remember Allah is through what has been revealed in the Book (Quran) and the Sunnah.