Is it permissible to take surplus food and medicine from the parents’ home without their knowledge and present it to the suitor, while informing him that the mother is the one who sent the food?

It is not permissible to take money from parents without their permission. Repentance is obligatory for taking food or medicine without the owner's permission. Repentance includes abandoning the sin, regretting it, resolving not to return to it, and restoring the right to its owner, either by returning what was taken or its value, or by seeking their forgiveness.