Inheritance from a Non Domiciled Person

[tax222]

Dear Tax experts

I want some tax advice regarding my Father’s tax affairs, and have three questions.

Qn1) My Father recently passed away, leaving behind 90% his assets abroad. He was visiting family for 2 months, when he died her in the UK after a short illness.
He was not born in the UK and had been Non UK domiciled, and non UK resident. He had his main residence & business abroad.
He also has a home in the UK, where he stayed when visiting his family over the last 21 years.(Visits were short & not business).The UK home was purchased in the early 80’s and is held in joint names/tenancy between husband & wife.

According to his will, he has left his UK home to his spouse (UK resident, ordinary resident & domiciled), and all overseas assets to 2 adult sons (UK resident, OR & UK domiciled).
Will there be any IHT implications if the sons brought the overseas cash assets into the UK? His bank account consisted of capital, income & interest.

Qn2) what will be the CGT implications on gains made from selling his overseas property? If the sons realise the gains, are we still subject to CGT under the 5 years residency rule? What would be the most tax efficient way to crystallize the gains?

Qn3) I believe the UK property automatically passes directly to his wife, as they were joint owners. Is he entitled to the 325K nil rate band, as the transfer is from a non UK domiciled to a UK domiciled spouse? If so, can her spouse carry his unused NRB giving her a total of £650k? He has not made any previous gifts to any family members within last 7 years.
What records must we keep if the revenue queries any of the above later.

Thank you very much and kind regards