Legal Question in Civil Litigation in Maine

Since you have not described what you mean by "his brother is becoming a problem" I cannot tell you a clear answer. If the problem relates to the agreement that your husband and his brother had regarding the loan, that has direct bearing on my response. If his brother is just a general problem in life, and it has nothing to do with the loan, then your husband has no recourse regarding the car. If they did not have a promissory note and a security agreement with your husband filing a UCC 1 financial statement with the Secretary of State office, then your husband does not have a lien or a right to repossess the car. The next time (if there is a next time) you or your husband wish to engage in a financial or business transaction, I suggest that you speak with an attorney in advance of finalizing any agreement so that you can protect your rights.

The fact that your husband is the borrower/co-borrower is not what would give him the right to posession. Rather, the Bill of Sale or title to the vehicle is what would control. If these title documents are made out to them jointly, then he has just as much right to possession as his brother. Unfortunately if the brothers are jointly titled and dispute possession, the police are not likely to assist and it is probably not worth the cost of a Court action for a Judge to Order the vehicle sold.