Inheriting and buying a house on UC/PIP

I am currently on UC and PIP with UC transitional protection for the severe disability premium (I was transfered over from income-related ESA). Following the death of my mother I am soon to inherit some money and am looking to buy my first home outright (I am currently in council housing). I understand that I am allowed to buy my first home with the inheritance and not lose benefits if I remain under the savings threshold butalthough I know I'm in a very fortunate position it feels very stressful and I have been in tears over it. I'm going to really feel it if I lose the transitional protection. I have severe ME. My questions: 1. Can I buy a home and not lose my transitional protection if I remain under the savings threshold as I'm assuming I'll lose the benefit as soon as I get the money from the sale of my mum's house and then have to reapply once I've bought somewhere? 2. At what point in the inheritance do I need to tell the DWP? We have probate so officially I have access to half of my mum's savings but I want to wait until the house sale so that I can get the money all in one go. 3. What sort of evidence do the DWP ask for with regards to the inheritance and house purchase? 4. If I find a property that is a bit over half of the inheritance my brother will pay me the extra - will that affect things? I appreciate this is a complex question and would happily pay someone experienced to talk me through it. I'm finding it so stressful. I realise also that if I buy a property that leaves me with over 7k in savings the question becomes a bit null and void because I will lose the transitional protection when I reapply if my savings fall back under the threshold.

Thankyou David, both me and my brother are executors - we inherit the money 50/50. So am I going to lose the severe disability premium protection whatever i do? I am looking to buy a 2 bed property so that I have somewhere where a guest or carer can stay - would that be deemed unreasonable? We currently have access to about 45k each and the will inherit a further 280k from the sale of my mum's home but local property is expensive. I cannot afford to live just on PIP once a property is bought.