I agree with Imme, you can't put your life on hold for Sweetheart even though you have just had a major breakthrough with her. She will be fine as long as you have your brother come in a few times so she will be more comfortable with him being there.
I have left Josey before for a few days and even for a week and she was fine when I got back, she might be a little ticked off at first or she might be glad to see you, it just depends but the main thing is she will be ok with it.
Go visit his parents, enjoy yourself, call and check on her for I know you will and then come back and get back into the usual routine, its the best thing for you and for her.