c'link wise - FTB, you ring up, he does an online application - very straight forward - all you need to do is let them know the change in care percentage. he will need to do a bit more, but you just need to notify of reduction in care percentage. as he is the one wanting more money, he needs to do all the paperwork on that end. so long as you notify within 14 days, you'll be fine. CSA you'd hve to notify and they would reassess

parenting payment is available to either parent - but is income dependent - so if he has a job with a reasonable income, he may not qualify. you would have ot go onto newstart allowance