JoyNampm,
If it is a frozen gas line, the oil dipstick heater would be of no use. When a gas line does freeze, it's usually at a low spot underneath the floor of the car, not necessarily near the engine itself. Once it thaw's out, assuming that is the problem, a can or 2 of the dry gas should take care of the water. To be sure, once it does start, I would throw another can into the tank and fill up with a full tank of gas.
What other things have you and your husband done to come to the conclusion that it is a frozen gas line?
How many miles are there on this vehicle? Does it turn over (crank) strongly? Does it even sputter when you try to start it? There are a lot of things that can go completely dead over night. A fuel pump, a coil inside the distributor, a cracked distributor cap or cracked distributor rotor, or even a broken timing belt come to mind. To check for a defective fuel pump, you can take the cap off the gas tank and turn the key to the run position with out cranking the engine and place your ear by the open gas cap and listen for a whine or slight humming noise. If the noise is present, that will tell you the fuel pump is working. You can check for a broken timing belt by taking the oil cap off the engine and have someone crank the engine over while you or your husband look down the oil cap with a flashlight to see if you can see the cams moving. If the cams are moving, the timing belt is intack. Another indication of a broken timing belt is when the engine seems to crank over too strongly. That's because with a broken timing belt, the camshafts do not rotate and open and close the valves, so you have no compression. With little or no compression the battery turns the engine over faster than normal cranking speed. Have you checked to see if the plugs are getting spark? You can take out a spark plug if you have the proper tools. I recommend a good 3/8 inch socket, a locking 9 inch 3/8 inch drive extension and the proper spark plug socket, usually a 5/8 socket on Toyotas. Place the plug back into it's wire and let it hang down somewhere where you can see it. Then, have someone crank the engine while another person looks for a spark. Do not hold the spark plug itself, while the other person is cranking it over. Also, do not lean on the car's fender while doing this or you could get strong jolt. It is easiest to see the spark in dim light. A safer way to check for spark is to go to an auto parts store and purchase a spark plug checker. This is a little device that goes between the plug wire and the plug itself and will light up while someone cranks over the engine, if spark is present. They cost less than $10.
The more information you give, the easier it is to help determine the problem.
I hope this all helps.
Let us know how things work out.
Mike