A few of the problems that can arise — and which can usually be avoided if you explain the full facts to a lawyer who is expert and careful enough to plan for them in advance.
Some of these examples may be upsetting to think about, but that is exactly why you can benefit from a hard-hearted lawyer who has seen a lot of life — and death.
Example: a couple are in a car crash, and the car bursts into flames. Who died first? The answer may affect who gets the property, if each left their property to the other but has different alternative heirs. It is normal for lawyers drafting Wills to cope with this by including words like “if they survive me by more than 30 days”.
Example: a couple own their house “jointly” — another legal word. This means that when one dies, the other automatically gets the deceased’s share. However, this can cause problems where a Will was written long before the death of the first or second spouse — especially where there is a “blended” family, with children of the parties by previous marriages or relationships.
Solution: it is wise to keep Wills under review, and to make a new Will when circumstances change.
In an intestacy, the legal test is biological relationship, not social upbringing.
Only two things could change that outcome:
One that expressly names you as a beneficiary — the intestacy rules then no longer apply.
If you were being maintained by the deceased and can show that reasonable financial provision was not made. This is a discretionary remedy decided by a court, not an automatic share.
So, unless one of those two routes is available, DNA proof that you are a half-brother will legally relegate your inheritance position to that of a half-sibling under intestacy.