Stepchild wants to see finances and money spent on his stepsiblings.

If it's "something like a trust, but not" (OP, you're not being very clear), surely this wouldn't be allowed?
It does sound like your husband only has a lifetime interest and the capital belongs to the kids, from what you say, but you aren't specific, so I would see a lawyer if I were you, and be completely open and clear, and find out what everyone is permitted to see and do. I wouldn't want to give information on here and presumably a qualified person needs full information to give a proper answer.

Just say No.

Batshit. Who has put him up to this? And definitely don't get involved in any conversations trying to justify yourself - this is entirely a DH problem.

Surely there is more to this though OP? Is Step child (I thought it was a son not sure where I got that from) normally an arse?

rather than telling him to fuck off or see this as the end of their relationship why doesn’t he sit down with him and discuss his worries? Is SS worried about university costs and your DH isn’t covering any of them?

How old are your kids?

it’s always better to resolve things in a mature manner than going straight for cutting people off. He’s 18 and your DH has brought him up so should be able to recognise where things coming from and that he is still very young with no real experience of the world

Your poor DH, discovering that he has a child who thinks like this...I would be devastated.

I think you should keep completely out of discussions with the SS as that will only fan the flames, and I don't think DH should discuss it with him anyway...other than to tell him (as calmly and politely as he can manage) that when he inherits it, in exactly the same way as DH did, he will be able to do with it as he thinks fit, as DH is now doing. And then leave it there.

Is he worried about Uni funding being impacted? Is someone feeding him wrong information? MIL had really odd ideas about inheritance but quickly adapted when told actual situation - but many people seemed to think she was right initally.

It sound very bad and rude that he's making demands.

However first step I would have though would be to explain his Dad income is his to do as he wants and at what point he'd get the sale of the assets - (it's not clear if it's when his Dad dies or when all that generation of siblings have passed on).

Then to point out your financial situation beyond that is none of his bussiness - and then if you want to point out you have your own assets and income.

The grandkids don't have any right to the money at all until all the parents are dead.

It is not his money. It was his granddad's money. His granddad's will does not state any of these conditions your step son is trying to implement.

Quite frankly the estate would have to be massive to fund the care of 4 people's care needs in old age.

He's getting entitled and greedy way too soon, that money isn't coming anywhere near him for decades.

If I was DH I'd be removing financial support as soon as possible or the kid is grow up thinking it's everyone else's job to fund his life. He needs to learn to support himself.

Don't even think about talking to them. This is a conversation that you must not get involved with. It would only inflame the situation. This has to be down to your DH

I suggest that before your DH speaks to his son, you and he sit together and make a list of the points that your DH needs to make. Your own income and child's father can be on that list.

Ok so as I understand it the assets from this trust are your husbands now and on his death will pass to your step children. Do you have a lifetime interest in your house or is that just your husbands? Your stepchild seems pretty mercenary which to be honest is not unusual in wealthy families but he/she has no right to see your husbands finances let alone yours even the income from this trust. Presumably your husband is generous with his children and doesn’t treat them differently to yours? I would be pissed off if I was your husband and would let him sort it out. It is none of your SC business how much he spends on you and your children as he has his own business too which he could leave to anyone. The SC sounds pretty entitled

So it sounds to me that the assets are fixed, and the 4 siblings have a life interest in the income generated from them. That income has nothing to do with you DH's children - your DH can spend this money as he wishes.

Then, after the 4 siblings die, the assets will be sold and divided between their children. It is only at that point that your stepchildren have any interest in the assets. Perhaps your stepchild does not fully understand this financial situation - he/she seems to think they have an interest now. I think your DH needs to sit down with them and explain exactly how it works.

Out of interest, what do you think your stepchild thinks is going on with the income from the assets? Is your DH spending ££££ on your children and he/she is jealous? How has your relationship with him/her been up until this point?

Tell them being an adult does not allow you access to other adults finances. He sounds ridiculous and entitled beyond belief.

That he's got a hell of a lot of growing up to do of he thinks he can demand access to anything of that nature.

It's none of his business and it never will be. Unless the person dies and leaves all their money to them. Even then what they spent in the past isn't remotely relevant.

If he can't handle that then he's not an adult is he?

I don’t think this is the case. Potentially the grandchildren have inherited with the children having a lifetime interest. Very different scenario.

Was there no precursor to this? How is the relationship normally? He feels that his dad is spending lots of 'his' family's money on your child and feels that should be reimbursed? It would amaze me if this has come out of nowhere.

I imagine it would be impossible to tell which money your dh is spending on what. Given that your SIL is using the money to fund her life without working, your dh could take the same approach to his finances, with his trust money paying for HIS essentials (contribution to mortgage, share of household bills, food, his car, clothes, phone etc.

So there's money from your income, and money from his trust going towards household bills.

Then anything else that is a luxury (a bigger share of the mortgage, holidays) or any money spent on your children is accounted for as coming from his own personal business earnings. Totally his choice how to spend his work income. Nothing to do with your dss.

Absolutely do not do that! He has no right to your justification or explanation. I wouldn’t engage at all.

If the son asked to see the finances and his dad said no why is it at the ending the relationship stage? That sounds very dramatic and unnecessary.

If your DH isn't doing anything that depletes the assets, then surely whatever he spends does not affect his son's' inheritance?

Has your DH mentioned this move by his sub, to his siblings (the others benefiting from the current income) to get a sense check from them?

In DH's place I would not say fuck off but I would take him out for a drink and explain he is way out of order questioning his dad like this. 18 is very young and goes with some idiotic behaviour.

What a jumped up little prick your stepson is 🤣🤣🤣

Grabby isn't living off a trust, grabby is thinking you're entitled to it, when you're not.

The grandson/SS hasn't inherited anything.

Their father has inherited.

What is left over when all the siblings are dead will be divided up and at that stage the grandson/SS will inherit their portion.

Yup never as clear as it seems if this is the case then the grandson has every right.

So your husband's share of the income is his to do what he wants with until he dies (and his siblings die) and then it goes to the next generation. The step children have no right to any of it till then and their father can leave his own money and assets any way he wants, which wouldn't be the one causing all the trouble at the minute. He has absolutely no right to see his father's finances or make any demands about them.

This is very hard to comment on without detail of the Trust and what the legal entitlements of children/grandchildren are. For those saying it is grabby well yes but so is the father living off the Trust. It would be different morally if it were the son asking the grandfather as the grandfather earned the money. However the moral argument is two people (son and grandson) both arguing over inherited money.

Your DH needs to be firm and tell DS to jog on. But first find out how this request came about. He's going to university, so potentially getting into a lot of debt.