Roth IRA

Vanguard mistakenly put $2,695 into my husband's Roth IRA account instead of regular brokerage account last year. We both retired. The financial adviser sent him a 1099R and asked him to amend his last year's tax return. What form should he fill out and submit to IRS. Should he amend it first prior to file 2022 tax return?

On his 1099R item 7 (distribution code is 8, J). Do they mean anything?

Thanks.