Can Son Claim 100% of Mortgage Interest?

[45095]

Mom/dad helped son purchase his primary residence in CA.  All names are on deed and mortgage. Mom/dad helped with mortgage payments in 2019.  Mom/dad own primary residence in another state. Can son claim 100% of allowed costs, interest, and points (points not financed)?

[Bsch4477]

Son can claim the mortgage interest and real estate taxes paid.  To prevent any challenge or confusion in the future it would be cleaner for parent to give the money to the son who would then make the payments.