Inheritance/Gift Tax - Non-Primary Residence

Looking for general tax guidance.

A parent owns a residential property that is not their main home and wants to transfer some or all of it to an adult child who has been living there for the last few years.

The property was bought decades ago for under 50k Irish punt, and is now worth in the high six figures - so if it was gifted would trigger a significant CGT bill.

The child has been covering substantial upkeep/repairs/maintenance of the house rather than paying market rent.

Is there any tax-efficient way to structure a transfer, either during the parent’s lifetime or through inheritance, without creating a very large CGT/CAT bill?