I do get your DH behaviour, I dont agree, but I do understand because my DH is the same with his kids
I was lucky that I only had one step daughter come live with us during her teen years, because mother could no longer cope, and I set down rules - here's your Family allowance, its for you to buy your fashion, go out , save up, pay your phone etc. It was £64 every 4 weeks - for a 13 year old, we were paying her clothes, shoes etc that were needed, feeding her, packed lunches, school dinners, this was pocket money. Then I found dad was subbing her to the tune of £20 a week phone credit and giving her money for fags - where as I was wanting to teach her she couldn't afford to smoke, phone and have a social life
So all the bad behaviour that mum couldn't cope with carried on - dad was enabling because of his guilt about being the absent parent for so long
I actually did leave her father over it, stayed away living in a hostel on £24 a week till he wised up that his giving her the money she was carrying on with the behaviours that were causing everyone grief
She still taps us for money now in her 40's even though her family income is a lot greater then ours - he just gave the family their spending money for their holiday - a holiday we cant afford to take
She asks for a loan of £50 from me ( and forgets to pay back ) so she can have a night out, is a days pay for me ( I work 20 hrs a week ) and it doesn't cost her a thought
His son, who he never had a good relationship with, who he never coddled, decided to get up off his arse, went to college to get his exams , took himself off to OZ, and 13 years later has a Sydney waterside apartment, a house in Melbourne and travels the world business class. That lad had had to work and hustle his way ahead, hes now head hunted , and married to a leading KC in Sydney.