What do you do when?

Okay ya'll here is the story, my best friend has a new girlfriend the first he has had in 10 months and well my sister and him are still in love with each other and my sister doesn't know how to act around him or his new girlfriend because we all have the same class together. the reason they didn't get back together sooner is because my sister had a bf and she broke up with him last night so she can wait for my best friend. your opinions please

I'd talk to your friend about it.
First find out if he still has feelings for your sister, cos he may have moved on and thats why he likes this other girl.
If he says he doesn't, on no account tell him anything, you don't want to mess up the relationship he has.
However, if he says he still likes your sister, i think you should let him know that your sister likes him too and then take a step back and let them work it out for themselves.
Good luck
*Gem*

Well if they are still in love then they should be together

Getting another girlfriend was your best friends decision. Maybe he's going out with her (his current girlfriend) for the right reasons; 'cause maybe he has actually gotten over your sister and likes this other girl, or the wrong reasons; to make your sister jealous. But nonetheless, your sister dumping her new boyfriend to wait for your best friend is no better than him using the other girl to get to her (if that is the case). So why'd your sister get a new boyfriend straight away in the first place, too? This tells you something... Regardless, it's a stupid decision on both your sister and your friends part. If they're in love they should have tried to work it out instead of what they did, that's what most people in love do anyways; they fight for their love instead of fighting with their love.

This is something your sister and best friend need to work on together, themselves. They should be the ones HERE to be asking for advice, not you, this is none of your business. It is your business to console your sister and friend perhaps, and not loose one of them in this process just because you're torn between being a sister and best friend. But it's none of your business to get between their relationship.

Sorry Hopeless but it is my business because they both come to me and ask me what to do. and the reason they are not together is because of my mom. it is a very hard sitution to explain. he has told me that he is NOT in love with his current girlfriend. it is just a comfront relationship. some people just don't understand it. it is kinda hard to not worry about it when you live with your sister and have her crying on your shoulder saying " i want my baby back" and your best friend crying too so yeah if you don't like it that is your problem. they have even said that they are going to get back together, the only thing stopping them is, his current girlfriend has seizures when she gets upset or mad. so they are trying to wait and see how they should tell her, but the thing of it is that his girlfriend knows that they are in love with each other. so what's next i have no clue but yes they do have the feelsings out on the table and I agree with you Amanda they should be together because they are in love and they are trying to work it out themselves him and my sister

Ohh well i think you should tell your best mates current girlfriend soooner cause the longer you take, the more emotional and all she'll take it.

Louii i totally agree with you thanks