Foster care/ Molestation/ brother

Hello so I'm not exactly sure where to post this but I need to vent. Recently about 9 months ago I became a foster parent for my brother. I learned in therapy about 2 days ago that where he recently use to live he was touched inappropriately as a means of punishment. I feel sick to my stomach not sure how to cope with it but at 9 I was molested and raped and this is how my virginity was taken. 
Anyhow, this all is coming out because I understand now why he is outlashing in school and saying he is alone, and sad since his mom died a few months ago. I'm not asking for pity I just want to know how to cope with this and accept that what it is happened. I just feel so sorry for my little brother because he is only 7 and he is so sweet and no one deserves to be treated this way.