Civil rights attorney Ben Crump, who is representing the Nichols family, tells TMZ ... Tyre's mother, RowVaughn Wells, is still not interested in watching the police body cam footage ... even though it was released Friday to the public.

We're told Tyre's mom is glad the video is out now, so folks can see what really happened ... but she just can't bear to see it herself -- just as she didn't when it was first made available to the family. Ben says she probably never will watch it.

As we reported ... the video is every bit as disturbing as Tyre's family and law enforcement described, and it all started with a traffic stop Jan. 7 in Memphis.

In the footage, you see officers wail on Tyre as he screams for his mom -- punching him in the face, kicking him in the head, using pepper spray and even beating him with a baton.

After a massive struggle, cops got Tyre in handcuffs and sat him up against a police car -- Tyre writhes in pain for nearly 20 minutes before he's given medical assistance.

Following a vicious beating from cops, Tyre complained he was having shortness of breath and he was rushed to a hospital, where he died 3 days later.

While gruesome, Crump says Tyre's mom thinks it's extremely important for the world to see how police treated her son ... and she hopes the video prevents a similar tragedy from happening to another family.

The video's already being linked to the beating of Rodney King way back in 1991 ... and we're told Tyre's mom understands the footage is triggering for many, and she's preparing to be flooded with calls.

The 5 Memphis police officers involved in the incident -- Tadarrius Bean, Demetrius Haley, Emmitt Martin III, Desmond Mills Jr., and Justin Smith -- have already been fired and charged with second-degree murder.

One thing Tyre's mom doesn't want to get glossed over ... the incident isn't just a hashtag for her ... her son is dead.