What is the ruling on a son stealing money from his deceased father's shop safe, when his father had a partner? Is it permissible to take the father's pension from social security after his death, or to benefit from the "Shifa" card, which reduces medicine prices?

The money taken from your father and his partner must be returned. Estimate what you took and be cautious in doing so. Give your father's share to his heirs after deducting your portion. If the partner or his heirs cannot be found, the money should be given as charity on their behalf. Commercial insurance is forbidden in all its forms, but there is no sin upon the heirs for taking what comes to them from it. If the "Shifa" card (health card) is free, there is no harm in using it. If it is for a fee, then its use is not permissible.