If the mafia boss only wants to be baptized in an attempt to not go to hell, it isn’t sincere repentance. I don’t know if you read about imperfect contrition
catholic.com/quickquestions/is-it-possible-for-a-person-with-a-mortal-sin-still-on-his-soul-to-die-and-go-to-heav
If he sincerely repents, he deserves to go to heaven. That’s the good news. Because we are all sinners. And by right, we don’t deserve God, but God wants us to want him.
As for a good person’s salvation, you don’t know. That’s the thing. Your mother might not be fully culpable for her sin. She might have repented in her heart.
I don’t know why this reminds me of the parable Jesus told…not exactly similar to this situation but it just popped in my mind… Matthew 20:1-16
I empathise with you because i have been in a similar situation, but you need to realize that God is just…and merciful. Sometimes we humans don’t understand bc we expect him to play by our rules