Can I file bankruptcy on this loan without it affecting my father?

Bankruptcy will affect your father is certain ways. First, if you file a chapter 7, you will receive a discharge of your liability for your debts even debts like mortgages/equity loans secured to houses. However, if you continue paying the equity line, you will have no problems with the bank. You could also reaffirm the equity line debt, but I would advise against it generally. The question with any home is how much equity you have in the home. Likely, your homestead exemption ($100,000 of equity protection) is enough. There are secondary questions about who contributed what to the down-payment of the home, who may have more equity in it, etc.. However, those questions would need to be addressed in a consultation.

Whenever you file bankruptcy, you are required to list all your debts regardless of your intentions to repay them or not. Therefore, you must list the home equity loan as a debt and, since it is secured by the home you share with your father, you must state whether you want to keep making the payments or not. If you don't agree to remain responsible for it, the lender has the right to foreclose if the payments fall behind. The language in the promissory note will define what constitutes a default. So, unless your father has the means to pay the loan himself, a bankruptcy is very likely to affect his ability to stay in the house. You should also consider whether you can exempt your interest in the house if you file bankruptcy. Every state has its own "homestead exemptions" but if you cannot fully exempt your interest in the house, the trustee could force you to sell it. In that scenario, I would recommend that both you and your father consider a Chapter 13 bankruptcy which would allow you to pay the trustee the non-exempt value in your home and other assets over a period of 3 to 5 years. A chapter 13 requires a steady source of income from which to make your monthly payments, and could also present an opportunity for you both to rid yourselves of the equity loan. You should seek legal advice if you want to explore the possibilities in a Chapter 13, as it is quite complicated.

If you are on the deed, then you have an interest in the property and you must disclose that. The mortgage affects the value of the home and thus, your interest, however.

If you have co-signed a loan with someone and file bankruptcy, the creditor on that loan will report that this loan is "involved in a bankruptcy" on your father's credit report. That is an accurate statement. However, unless a mistake has been made, that report should not damage your father's credit score.

If you file for bankruptcy, the bank will likely want you to reaffirm on your portion of the note.

Maybe. Unless you reaffirm your mortgage debt during bankruptcy proceedings, your father will become solely responsible for repaying the debt. And if your father does not make the payments on time, the creditor can take legal action to foreclose on the property to collect the debt.

It may depend upon how much equity there is in the property. The loan will not be problematic as long as the payments are current, but the value I your ownership interest could be. You should retain a bankruptcy lawyer to make sure you protect what you have I the greatest extent possible.

Only your debts can be discharged in your bankruptcy. Because you and your father are co-makers of the note, the two of have joint and several liability for the debt, meaning that the creditor may sue either of you for the full amount of the debt upon default.