Sadly I know exactly, as I lost both my parents before I reached the age of 30 
My dad died when I was a small child, and his inhertence passed to my mum. That was all used up supporting us growing up with a single mum. Following my dad's death, my mum was always very open about her arrangements. She took out a plan to ensure her funeral was paid for as she didn't want to make things any harder for us children. She was always clear that her will simply split everything 50:50 between my sibling and I. TBH, she never had much cash so I didn't really expect she'd have much to leave us.
Sadly I lost my mum a few years ago
. It broke my heart, she was far too young. As expected, she had modest savings in her bank. What we hadn't expected was the value of the house (which had been mortgage free for years, my fathers life insurance having paid it off years before). I still lived with my mum and hadn't paid any particular attention to house prices, so we were surprised when the house price alone bear pushed us over the IHT threshold.
Anyway, we split the house equally. I bought my sibling out and have remained in the property with a 50% mortgage. The way I came about the asset was horrible, but I have to admit that it came at a pivotal time in my life. No way could I have afforded a house otherwise, and I know all my mum ever wanted was to provide for her children and make sure we were ok. So I like to think she'd be happy that I stayed in the house, decorated it nicely and am now comfortable thanks to her.
We were all surprised to discover we were entitled to a death in service benefit from my mum's pension, so we also received an entirely unexpected cash sum from her pension scheme. So I have equity in a house and some savings as a result of losing my mum so early.
DH's parents have a mortgage free inherited family house which has increased in value recently and appear to have a reasonable sum of money in the bank, but no idea really. They aren't great with cash, his mum fritters it on junk. We have no idea about their will, but there's a good chance lots of their estate will go to IHT (as the house alone pushes the estate well over the threshold) or that it'll will go on care. I know my DH isn't planning or expecting anything from his parents particularly.