I expect the answer will that I need to see the detail of documents I don't currently have access to, but I'll ask anyway!
DF and DM owned their house at tenants in common. When DF died, his half was left equally to DB and me. I think in a trust. Basically in a way which allows DM to stay.
My own will states that everything of mine is to pass to DH, or if he predeceases me, then DC (in trust until they are 25).
What happens to my quarter value of DM's house if I die before she does? Is it already 'mine' such that it would follow the stipulations of my will, or would it be subject to something in DF's will?