Friends?Love?Hearteache?I need Help(my lil sis)?

Ok so my ex Brandon just recently started liking my friend (nicole)but here is the thing he is another one of my friends(larissa)2 weeks ago i broke up with him because he liked Larissa and wanted to start her.so then while we were still datin he went out with Larissa and I found out and told Larissa that we were still datin so we both broke up with him...but when he found out that i had something to do with his and Larissa's breakup he god super mad and txted me things that should not be repeated. Then he met the new person at our school. Nicole and now he wants to date her.she says she'll go out with him so he'll break up with Larissa and then Nicole will break up with him so he can date me again..is that right? should we do this?Brandon and I were friends before anything now we are really close again after the breakup...but will Larissa get mad if she finds out that i had something to do with hooking him and Nicole up..or what if she finds out we're .HELP!!!!!!!!