Dylan Scott was fatally shot in his car by a Florida police officer who tried for several minutes to get him to cooperate, but Scott's mother thinks the cop could have done more to save her son.

Pennie Kendrick tells TMZ ... even though Dylan refused to comply with the officer's orders, she believes other tactics -- such as tasing him -- should have been used instead of a gun.

Kendrick says they didn't have to kill him, and she's especially upset because she claims the cops knew her son was suicidal so they should have handled the situation differently.

As we reported ... Scott's mother called the Hillsborough County Sheriff's Office in July when he was wanted for burglary, saying her son left a note that he wanted to die by suicide by cop. She says at the time she urged cops not to shoot him given the circumstances ... and they were able to peacefully arrest him back then for outstanding warrants.

Kendrick claims his time behind bars left him traumatized -- she says he was beaten by other inmates and didn't complete his addiction treatment.

She tells us all this led to more problems, and ultimately he became broke and was living in his car. Scott's mother believes the reason he didn't comply with the officer is that he was scared to death ... but she thinks he would have peacefully surrendered.