Giving up masturbation

Q: I have a problem (of making ghusal farz by hands) for the last 5 years. I have tried my best to leave it. Once, I have been able to leave it for 3 months but after that I was caught by it again. I have asked forgiveness every time from Almighty Allah and alhmdulillah He has blessed me every time, but I couldnt leave the sin.

I am average in ibadaat. Sometimes I perform salaah 5 times a day for a month or few months and sometimes I leave it out for a few days and sometimes I dodge a few prayers.

Kindly tell me a simple and easy solution to leave out this sin. 

Benefit of reciting Aayatul Kursi

Q: Can you please provide guidance on the benefits of reciting ayat-ul-kursi? I have been told:

1. Recite ayat-ul-kursi before going to bed.

2. Recite ayat-ul-kursi after making wudhu.

3. Recite ayat-ul-kursi after reciting your fardh salaat.

Please provide insight into the benefits of reciting ayat-ul-kursi for the above 3 occasions and also if there are any other occasions when you should recite ayat-ul-kursi.

Performing fardh salaah in a car

Q: While travelling in a car, my family prayed the obligatory namaz sitting in the car. Later I found out that sitting while being able to stand invalidates namaz. It was also raining heavily so is the prayer valid as it was done out of ignorance or should I tell my family to repeat those prayers?

If they have to repeat it, should it be prayed as qasr?