Discretionary Trust and Share of property in a Will in future...re HB in UC

Hello all
I have several chronic conditions and thankfully have been awarded Support Group in UC including rent for current property. I also receive lower rate DL PIP.
My mother has created a Discretionary Trust in her Will using a STEP lawyer which I think means that I will not be charged IHT when I receive the inheritance, to be shared with other adult children and grandchildren. This will be a third of a London house and a modest amount of cash, after IHT paid.

My concern is that if I inherit a share of her house as she has planned, it may mean that I am not entitled to receive HB in the future which I will need, especially if I have to move from my current low rent property. I don't understand the rules, Mum doesnt either.

Or would I need to use the inheritance up until it falls into the 16,000 or under HB entitlement threshhold? I would rather not use up a lot of the inheritance on that as I will need most of it for living needs, special treatment for my illnesses etc which I will not get on the NHS. Would it be better to ask that I don't inherit a share of the house in London (a third) and just inherit some cash, which will not be problematic for IHT? Whatever happens, I need somewhere to live, after all. Many thanks for advice given. Ostia