So if j and Harley had twins (1 boy,1 girl) and their son hit a rough patch and started cutting. How do you think Harley, j, and cp would help him with that?
Harley and Joker would want their daughter to sit back and let them handle it first. If they have multiple kids and one has a problem theyd try and handle it between the three of them. Joker would be with him physically prevent him like sleep next to him so he doesnt sneak away to cut or bring him on business stuff. Harley would show him coping methods like bazooka lessons or give him her mallot to whack someone. The daughter would sneak to him in private and check on him, let him vent, kiss the scars.
I had a previous ask a while ago about if the daughter cut and I still firmly believe this, theres a lifetime movie called painful secrets or secret cutting depending on your region. Theres a scene where the father brings a knife into his daughters room and rolls up his sleeve and says if you want to cut something cut me. That, to me, is perfect for joker and howd he reaction to his kid self harming. Hes not great with feelings but he knows hed do anything to stop his child from being harmed.