Client is looking to buy a house in cash but only has IRA assets

The title mostly says it all.

Client is HNW and is a strong income earner. But spends most of their income and has little saved outside of the IRA and 401k which they diligently use.

They own property outright and want to buy a different property in all cash. They called me today to discuss cashing out money from IRAs to make the purchase with the idea they could replace it when they sell there current home.

I explained I don't think we could really do that without doing something funny with rollover windows and would more likely then not be creating a huge tax liability. (Share any info on this if your familiar. Moving from fidelity to say Schwab to take advantage of rollover window)

I explained they could use a HELOC to be an artificial cash buyer. When they sell there house they can close out the HELOC.

Option two would make their purchase contingent on the sale of their current home.

Use a asset based loan as a bridge based on any money they hold in non-qualified accounts or use some other sort of alternative lending.

Any other options I'm not thinking of?