This is inspiring in someways. Several relatives were in the same situation your birth mother was in -- but kept the kids. Bad idea. Now my cousins are just like my aunts and uncles. Dozens (yeah...I know, dozens of cousins...) are in jail. Several are still loose on drug charges. One, last I heard, was charged with a hit and run and fled to Mexico with some narcotics (her mother also killed my grandmother though neglect, so compassion runs high in this family).
However, your siblings are still young and I'm sure they want your help. A few -- very few of my 'kin' did make it through and are now productive members of society instead of leeching off the rest of us.
Like I always say...you don't choose your relatives...