Does the agreement to split profits equally remain valid if I realize that my partner is not doing any work, but rather investing the money with others without my knowledge? What is the ruling of Sharia on not giving me the full profits? Is it permissible to give him a percentage for managing the money on the condition that he gives me the full profits? What is the ruling on his lying to me?

What your friend did—lying and disposing of money without your permission—is impermissible. He must guarantee the money if it decreased or was damaged. As for his entitlement to profit, there is a difference of opinion among scholars. If an agent in a Qirad (profit-sharing) contract entered into another Qirad with a third party without the owner's permission, the second Qirad is invalid, and the first agent becomes a guarantor. The profit resulting from this action is a matter of dispute. Some scholars are of the view that the profit belongs to the owner of the capital, while others believe that the second agent is entitled to a fair wage (ujrat al-mithl), or is entitled to nothing, because he acted with another's money without their permission.