if he is acting like a kid. treat him like one
set a chore board up: itsa chart of certain chores which will earn him pocket money if he completes it.
dont set the rewards too high. just have it where if totalled up al the chores complete would earn him enough for food and a couple reasonable gifts. (no extravagance)
the reason i say this. is by setting a low income. means he can get something by oing something but get nothing by doing nothing. .. but also may make him come to the realisation that he can earn more and earn it faster by getting a proper job and not reliant on parents pockets.
however by continuing to let him just beg for money is just going to continue him getting it. cutting him off will just anger him and up his game. thus becoming more harrassing and more abusive until someone gives in.
and that will become the new standard level of abuse he will apply every time
(yep all kids do that. they hear no, but then pressure 10% more. and if they get a yes. they then use that 110% pressure every time. if they get a no. they add 10% more and if it works they apply 120% pressure every time. endlessly upping it)
so if your at the point of cutting him off you have to be able to follow through with kicking him out. otherwise he will always win by upping the abuse game if never asked to leave.
so thats the options.
* set some rules which earn him rewards and see if he can change. stick to them. dont deviate, dont give in
infact make it a game where you do the chores and you get the rewards instead. then challenge him to beat you at the chores
* set a ultimatum. where he will be kicked out if he doesnt settle down
if however the family chooses to just feed his demands. then there is not much you can do. leaving you personally the only option of you leaving the situation and escaping the stress.
the problem is that families do too much of the loving friend.
EG
kid: 'i want some money'
parent: 'sorry i cant afford it'
kid: 'you dont love me, you hate me and want me to suffer blah blah blah'
it doesnt matter how much love is shown 23hours 55minutes of the day. if a kid wants money in one minute and gets told no. anger grows in 4 minutes and completely makes the other 23hour 55 minutes seem like a wasted effort and pointles use of energy as the kid has blocked out all that
its not about going from best friend to prison warden at the click of a finger. its about having rules and boundaries and a way to show what gets rewarded and what doesnt
sometimes having a calm 'heart to heart' conversation about the boundaries is a task in itself trying to find the most calmest time to talk and try to get it said without turning into an argument.
the short effective way is just put a chart up of chores and rewards or a rule list up. no big conversation no back and forth.. just there it is black and white
there are other tricks too
if you are afraid of saying no. then say a choice.
yes you can have $20 but we are selling your TV
yes you can play on a game but then thats less time for watching TV
yes you can leave your brocolli but you'll have to wash the dishes
That’s some truly heart warming advices, I appreciate your taking your time to write a long post yet I read all of them, and this spoilt brat is not typically poorly educated, he come from English education graduated from computer science, you can say he is very smart very calculative very aware of what’s risk and reward ratio, he is basically taking all possible advantage on leeching on whatever he can get from his providers, I think he learn a lot of thing from YouTube about how to be a total jerk and be a shameless leech and still nobody can get rid of him, I think he is totally womanised in provider hunting ability and harness the skill to a new height, since many politician can get away with all this same excuses he will also get away with being a total jerk, I will consider about the advices you provided, despite it seem like a losing endeavour to me.