Coolant leaking is easily identified. You can empty coolant first and filled up water for checking. Major check points are tubes and connections.
If your car is really old, radiator may be rust, as shown in the lower right corner in the picture below. It is a little bit involved to take out the radiator: removing the front bump and AC evaporator.
Radiator with front bump and AC evaporator removed
New radiator with fans behind before installation
No comment about your AC because of lack of detail.
I would clean up vents, replace cabin filter and recharge R134 if there is no AC leakage.AC comes back to life for my 2 old cars after cleaning up and recharging.
