Pre-Tax contribuitions to HSA

[jala]

Employee covers spouse under HDHP. Each are over 55 years of age and eligible for catch-up contributions to HSA.

I understand that the spouse can open separate HSA account and deposit his catch up contribution to his account.

Question is:

Can employee defer from her paycheck, on a pre-tax basis, the amount of her spouse's catch up contribution OR

is she only able to defer from her paycheck, on a pre-tax basis, just her catch up amount and he would have to file for his credit on personal income tax return?

Not sure about the limit reported on her W-2 whether she can defer total catch-up of $2,000 (for both) or if only $1,000 can be deferred and they would have to file Form 8889 for $1,000 for her spouse on their personal income tax return.

Appreciate your help with this one!