In regards to changing a final parenting plan?

hi i have a 14 mth old baby boyu who has been diagnosed with duchenne muscular distrafy. my ex left me at 4 mths pregnant i filed for divorce after my son was born. he didnt show up to any of the hearings so now it is finalized. my ex just got released from prison yesterday and want to modify our parenting plan. he has a history of drug use gun charge along with violent charges. im wondering if he has any chance getting visits with my child who doesnt know him at all.thanks!!