Claiming a dependent either qualifies for the $2000 child tax credit (not in this case) or a $500 "other dependent" tax credit. Removing the dependent would require repayment of that part of the credit. Additionally, if your father is a qualifying person for head of household status, then switching to single status would increase your tax rates and lower your standard deduction (unless you have other qualifying dependents). I don't know why the repayment would be only $423. Are you playing around with the numbers in your finished return? Never do that unless you plan to amend your return and start by clicking the Amend button before making any changes.
Two further points.
1) Our information as of now is that the stimulus payment will be recalculated on the 2020 tax return and people who qualify then may be paid then if they were not paid now.
2) You can claim your father as a dependent if he meets the following two tests:
a) his gross taxable income for 2019 is less than $4200,
b) you paid more than half his total financial support.
You do not have to live together to claim him as a dependent. However, to also claim your father as a qualifying person for head of household status, he must either live in your home, or you must pay more than half his living expenses in the home where he does live.
Remember that social security and disability payments may not be taxable income but they do count as "support" that he provides himself.
If you can't claim him, you should amend. If you can but don't want to, you don't have to. However, if he files his own tax return and qualifies to be claimed by you, he must check the box that says "I can be claimed as a dependent by another taxpayer" even if you don't want to claim him and he doesn't want to be claimed.
