Losing your mother is a terrible thing and I don't know DeAngelo Williams personally, so I'm would not dare assume that he would do something as terrible as lie about it for his own gain. Regardless, context is everything and the timing of this from him is disappointing and exploitative towards the fans and this franchise.
I feel for his loss. I can't respect how he brought it up on his way out the door like a scorned lover instead of mentioning it at any point during the nine illustrious years he had with the franchise, including public moments the franchise specifically dedicated to his mother. It hurts as a fan because I thought he was better than that.
Did he play RB or did he come in just to carry the ball? What I mean by that is that there is a lot more to playing RB in the NFL than just carrying the football. Being able to pass protect is one of the key ones, especially if you have Byron Bell playing LT.
He rushed for 1000+ yards and 15 TDs in high school. Can't find much about college except one game where he was put in and got 150 yds on 10 carries. He seems like a very capable backup at the very least.