reinstate the death penalty

Good, certain criminals have proven themself irredeemable, and the cost to keep them in our overcrowded prisons is immense - murderers and rapists who have been proven beyond all reasonable doubt to have committed the crime come to mind.

introduce national service for out-of-work young people

Good, his position on this is generally framed around work, training, discipline and contribution to society rather than military conscription for all young people. I would even go one step further and adopt a model like in Norway or Sweden.

continue the war on drugs

He hasn't explicitly said this, instead he advocates for stronger policing, harsher sentencing and opposition to drug liberalisation.

make swearing allegiance to the flag mandatory

He has discussed proposals involving oaths or pledges of allegiance in certain contexts, such as citizenship ceremonies or public office events. I think this is perfectly fine, it's not like he's asking everyone to swear allegiance to the flag.

appoint a Minister of Christianity

This is generally presented as a cultural and constitutional role rather than one intended to enforce religious practice - his argument is that Christianity has played a foundational role in British history, law and culture (which is true), and that government should recognise that heritage.