Filing where there is a joint bank account but filing separately

I live in VA and have a foreign bank account with my child (over 21) as a joint account holder. That account received interest from the FDs with the bank. There was also a deposit that was specific for the child. We are filing separately. My questions are:

1. How should the interest earned in this bank account be distributed amongst us?

2. Should the deposit meant for my child be split evenly as well or that deposit can go against my child's filing

3. How about when it comes to Foreign Tax credit on the interest paid? Do we spilt this in half as well?

 

THanks in advance. Really appreciate and enjoy being in this forum.