spousal IRA contribution for 2023

My spouse and I are both 74.  I am still employed.  My husband is a civil service retiree.  We would like to make a spousal contribution to his traditional IRA for 2023 based on my earnings. I am unable to contribute do to  investing in a retirement plan at work.   Our investment person wants to make sure it is allowable to make a deductible contribution for 2023.  He says it will increase our RMD and may not make sense.  Can you give me any advice.