Why did Imam Khomeini not encourage his grandson to perform midnight prayers?

Imam's quiet companion and pleasant companionship

Ahmad Khomeini had great virtues, sacrificed himself for Imam

Source: Ambassador of the Imam and the Revolution (Memoirs of Hojjat al-Islam and Muslims Seyyed Ali Akbar Mohtashamipour)

Imam Khomeini called for the boycott of Israel in 1967?

A memoirs and statement by the supreme leader

Imam used to say hello and greet first

Ayatollah Seyyed Hossein Badla

Imam never gave up mid-night prayers even during exile, tough times

A memoir by Hujjatal Islam Haj Ahmed Agha Khomeini – Imam's son

Imam did not like to use pulpit out of respect for great scholars.

Narrated by: Sayed Ali Khamenei, Supreme Leader of Islamic Republic--Taken from: Shahed Journal, no. 195

Imam attached great significance to reciting holy Quran.

A memoirs by Hujjat al-Islam Aashtiyani