Yes. It was shown in previous episodes ( it was shown that his mother gets arosed and asks him to help her) correct…
i think that scene was his mum dying from overdose of heroin, asking him help, initially he wanted to call ambulance then hesitant due to abuse of his mum (he hated his mum), so he just watching her die slowly
ML's revenge is out of logic, your dad killed her son (or maybe his boss did) and she killed you dad, fair and settled, why he went on revenge back on her family...i doubt the FL will do anything to him except using soft moral teaching caring lessons for him and wish he let go of his anger