Sorry, but insurance like that just isn't worth buying. If your brother could challenge a joint tenancy in court, he could challenge a living trust, too. That's because his reasoning would be the same: probably that you exercised undue influence over your mother, or that she didn't understand what she was doing, and as a result he was cheated out of his rightful inheritance.

However, if your mom put her property into joint tenancy with you only to avoid probate -- and her goal was not to give you half ownership of everything now -- a joint tenancy is not the best method. For starters, if the value of the interest she gave to either you or your husband exceeded $13,000 in one year, she was required to file a federal gift tax return, though she wouldn't owe any tax right now.

It would have been preferable for her to keep the real estate and create a living trust herself, naming you and your husband as beneficiaries. A living trust is relatively difficult to challenge, because your mom's continuing involvement with trust transactions would help to show that she understood what she was doing. With the bank accounts, an easy way to avoid probate would have been to name you and your husband as payable-on-death (POD) beneficiaries, using a form provided by the bank.