Is it possible for you to change your stream? because clearly if you are not interested in engineering, medical, maths or science, it is best that you drop them.
If you're interested in economics, finance, accounts, you could take up courses related to these. But if you don't plan to do any sciences in the future, and you can't change your stream, try to finish your spm the most convenient way as possible. It's still January, and it is not too late to change and study something that you like, rather than putting 2 years, studying something you don't like and you don't plan to use at all in the future. 2 YEARS IS LONG AND TRUST ME IT WILL BE PAINFUL STUDYING SOMETHING YOU DONT LIKE!!!!
I suggest you list down what you really want to do on a pieces of paper, and it will help you make your decision.
TS said he is taking SPM this year so if changing stream is an option TS would have more new subjects to cover from Form 4 onwards while he is now in Form 5 already. That seems more heavy than brushing up on the current subjects TS is weak at.