Lmao there is no way I can sympathise with the father (and the mother). What he did was inhumane. No matter what, they left three children out on the street to someone they hadn't had any real contact with in years. If Wahei happened to be on a business trip or working/out overnight, they would have slept outside.
I mean, they should really be punished for neglect.
And the kids as well, they've had to just reason "that's how he is" but that doesn't make it acceptable. They've had to grow up way faster than their time. The MC and elder sister had their childhood robbed of them.
This chapter was honestly the worst. Sure, suspend disbelief when he didn't call the authorities or take them to their mother (doesn't matter if they're "an inconvenience" to her, they're an inconvenience to him too), but this chapter just felt like it was trying to justify or rationalise their horrible parenting decisions.