Is it permissible to photocopy study notes from the notebook of a person who does not pray, knowing that I am unaware of the source of his money, or is it obligatory to photocopy them from a person who is observant of prayer?

There is no harm in seeking help from one who does not pray. They should be treated with gentleness, compassion, and invited to the faith, recalling the words of Allah Almighty: "Speak to him gently, perhaps he may take heed or fear," and the words of the Prophet, peace and blessings be upon him: "By Allah, that Allah guides one man through you is better for you than red camels."