Co-own a 2nd home w/son. How to claim and how much to claim.

We co-own a home with our son.  He is on the loan to help his credit, but we make all payments and have put our money into the home.  We're both listed on the loan and tax statements. The question is two-fold.  1. Can we claim the interest or does he get to/have to claim a portion of it?  2. Are there limits of what we can claim since it is a 2nd home for us? Our primary home was purchased in Feb. 2016, but refi in 2022.  Bal is $583k.  2nd home was purchased April 2023 and bal is $468k.