Whitney Purvis‘ baby daddy is speaking out about his ex’s arrest for involuntary manslaughter — saying he hopes this will be a turning point in her troubled life.

Purvis’ ex-boyfriend Weston Gosa tells TMZ … he hopes her arrest “will be the wake-up call Whitney needs to get the help and recovery she needs.”

He went on to say he and his family are “deeply sad to hear the news, and our prayers are with the victim’s family. We’re praying justice will be done for the sake of the victim’s family.”

We broke the story … Purvis was taken into custody Monday in Georgia after authorities say she intentionally distributed a deadly mixture of fentanyl and xylazine — a combo known as Tranq — that led to the fatal overdose of John Mark Harris.

Our sources told us Tuesday she’d been placed on suicide watch while detoxing during drug withdrawal behind bars.

Gosa also addressed accusations Purvis previously made against him and his family — particularly in the aftermath of their son’s funeral last month. He tells us he hopes people can now see the accusations she made against him and his family are lies and manipulations to make them look like the bad guys, after her behavior at the funeral.

As we reported, she showed up late to the services and was not allowed inside to attend.

He emphasized their son, 16-year-old Weston Jr., was receiving proper care before his death in June, adding … “We want to make it very clear we have documented medical records to show that our son was seeing his doctors and getting his medication daily. His most recent appointment at CHOA was April 4th. The accusations she has made are disgusting and sad.”