Relationship with his mom might prove interesting. Was he considered the "loser" in the family. He helped her with apartments she owned in Florida.
I'm sure the authorities don't want to make a big deal of it, but no doubt they're talking to the mother. Evidently she's quite old.
I don't think the family saw him as a loser. Eric, the only one who's talked to the press, evidently believed he was "rich", worth a few million, whether that was true or not. He also said his brother was "weird", and not particularly friendly to him. Evidently Steve did look out for Mom, though at a distance. Eric also said Steve was nice to the girlfriend, apparently willing to do things for her he wouldn't do for other family members.