I am the POA for my dad. His house has high capital gains taxes (bought it 1983) and low property 19 (CA) tax base. Can I keep property 19 tax base on a 1031 exchange ? ( I have heard no)

Could I do the 1031 exchange and rent out the house for a while and then move him back in as his primary residence and apply the property 19 tax base at that time ? I believe you have 2 years to claim the property 19 tax base and he must have lived in it for 2 of the last 5 years to qualify as a primary residence ?

Could he claim the property 19 tax base if he bought a new primary residence and also did a 1031 exchange on the original primary residence ? We are renting the property now and I know we have to meet the 1031 guidelines to do the exchange.

The motivation for the sale is he needs care right now and I would like to have a larger more functional house available for him to be cared for.

Maybe there is another method to minimize capital gains taxes that make it easier to sell and keep the property 19 tax base ? I have heard a few methods,

Thanks!