No, "abandonment" does not change someone's ownership rights, and if she is on the title, she is an owner. There is no way to remove her and take away her ownership interest. If your friend cannot voluntarily work something out with her--which will be almost certainly the most cost-effective way to proceed--he can file a lawsuit in chancery court (a part or division of county court) requesting that the court order the sale of the home and that the proceeds, after paying costs of sale and any mortgages, be distributed between the owners. In the lawsuit, he can ask the court--but is not guaranteed to succeed--to award him more than 50% due the extra costs, amounts, etc. he has paid. Since such a suit can be proceedural complex, he really should  retain an attorney to help him, so he should factor in the cost of the lawyer, too.