Multiple nil rate band use?

I have an estate where W has been married twice. First husband left his estate to W. She then remarried husband 2. W then died leaving her estate in a life interest for husband 2. Unfortunately husband 2 had lost capacity by this stage and could not agree a variation of the Will. There was no power to terminate the trust. Husband 2 has now died (within 2 years of wife) and the two estates will aggregate.

Is there anything that could be done to make use of the NRB from husband 1 at this stage?

This is an interesting question. My immediate thought is that since you imply that we are within two years of the death of W, we could vary W’s estate such that 2x nil rate bands go to non-exempt beneficiaries (claiming her own NRB and a TNRB from H1) with residue to H2 absolutely. H2 then uses his own NRB at his death - so three have been used altogether.

It’s more difficult to grab RNRBs in this way but might work depending upon the ownership of the home (also whether H1 died pre-2017).

I don’t know if the existence of an intervening life interest affects this reasoning. Do other members have any thoughts as to whether this could work?