IHT discount for jointly owned property

Reviewing the tax implications of winding up 2 family protection trusts (we were not involved in the creation) Each trust was created by the respective spouse and each settled their 50% share of the home,. Post 2006 lifetime IIP so a CLT on creation but under nil band. Husband died and value of GWROB (house) now results in IHT payable as wont get spouse exemption or RNRB.- Now looking at winding up trusts and distributing assets,. If wifes trust is wound up and 50% share appointed to her this is of sufficient value to use her NRB and RNRB, I am assuming if we appoint other 50% share from husbands trust to the kids the wifes share of property would qualify for a 10% discount on her death due to being jointly owned.