BUFFALO, N.Y. — A Buffalo man who admitted to causing severe injuries to a toddler he was watching – the second time he's comitted such a crime – will spend 15 years in prison.

Marcel Brooks, 26, of Buffalo was sentenced Friday to 15 years behind bars with five years post-release supervision. He pleaded guilty in June to first degree assault for shaking Devyn Grabowski in October. Brooks was the boyfriend of Grabowski's aunt, and was convicted of second degree assault in a similar incident in 2010.

Grabowski was 22 months old, and his family initially didn't think Grabowski would survive after Brooks hurt him.

"You see him. He's fighting and fighting and fighting, so he can stand up on his own, and do things with his left hand," his grandmother, Denise Grabowski said.

Brooks was defiant, smiling and winking in the courtroom on Friday.

Denise Grabowski told the judge of all the difficulties facing her grandson. She was disgusted by Brooks' demeanor.

"Seeing him in court today with a smirk on his face.  It was like I can imagine what other grandparents and parents would do.  You just want to go there and you just want to strangle him and say, "Why did you do this to this baby? This baby didn't hurt you at all."

Erie County District Attorney John Flynn says he's glad Brooks will be locked up for 15 years with no chance to appeal.  He believes this case is a cautionary tale for families who need to leave children in the care of others.

"Not only was this boyfriend not qualified, not preapred or competent to watch a kid because he shook the baby up," Flynn said. "But he's a career criminal who had a prior shaken baby case before and that's unconsionable."

Devyn's loved ones are happy for some measure of justice and closure, as he battles to have a normal life.

 "When you go to a place where Marcel is going, when people find out what you're there for, when you harm in innocent little child, you're taking your own life in your own hands," Denise said of Brooks prison sentence.

Devyn's family says doctors aren't sure if he'll ever regain full motor function, but he is improving with the help of therapy.

"Clearly, all we can do is go up from here," said Devyn's father, Jeffrey. "And hope and pray to God that he makes a full recovery."