The CSG déductible connue, calculated on heritage revenues, is a French social security contribution that applies to certain types of income, including certain types of investment income. If your father does not have any such income, you should indicate this by correcting the information in case 6DE.
If your father does not receive a Form 2042CK, it may mean that he does not have to declare income from his B&B for this tax year. However, it's best to check with the tax service as there may be different rules depending on his specific situation.
The UK state pension is considered a social payment in France and should be reported on Form 2042 (section 2, case 1AI).
The military pension should also be reported on Form 2042 (section 2, case 1AI).
The 75 euros per month that is being taken from his bank account is likely a monthly pre-payment of his taxes. The "Fiscal" number is likely a reference to his French tax identification number. It is best to reach out to the French tax service for more specific information, as rules and regulations may change. They may also have a guide or an online platform for non-residents which might make it easy for you to file taxes for your father next year.
