tWitch’s family is done with his widow, Allison Holker, continuing to make shocking allegations about their late son ... and they're now taking legal action against her.

Connie, tWitch’s mom, went off on IG, blasting the "misleading and hurtful" claims in Allison’s new book about her son's life and death ... saying that she can't solely focus on her healing anymore 'cause she's gotta protect his name and legacy, and defend his honor.

The whole Boss family came together with another statement backing Connie, slamming Allison for her “disrespectful and evasive actions” since Stephen’s passing ... and calling out the “misleading, unproven accounts” and the inconsistencies in Allison’s book.

They’ve got a lot of questions that still need answers, so they’re getting legal counsel to dig into the situation, and they’ve also started a GoFundMe for donations, which will go toward covering legal fees and related costs.

Connie and her family have already shut down Allison's claims that tWitch hinted at being sexually abused by a male figure in his journals, calling that completely unfounded. They’ve also brushed off her allegations about tWitch having a serious drug problem.