Surrender of an IPDI which then passes into a FLIT

I am working on a matter where the husband left his 50% share in his home on IPDI trust for his wife for life then on her death to the trusts of the residuary estate (no overriding powers). The residuary estate is left on FLIT (for wife for life with the usual overriding powers), with a default gift which gifts the trust fund to the son but only “if my wife dies before me”. The second default, which does not state it is subject to the wife pre-deceasing, is to other family members (nieces, nephews etc).

Wife is now moving to a care home so the property will be sold and she has no need for the income from the IPDI’s share of the proceeds or from the FLIT. Wife wants to accelerate all trust assets to her son and to bring the trusts to a close. We are more than 2 years from the date of death.

To simplify matters, if the trustees exercise the overring powers in the FLIT to pass all assets in that trust outright to the son, then subsequently surrender the wife’s interest in the IPDI to accelerate that to the FLIT fund, does this achieve the outright distribution to the son as a PET from mum, or are there any complications due to the interest in the home passing through two settlements? Would wife still get downsizing relief for RNRB/TRNRB?