If the account was owned individually by your late mother-in-law, it would be acceptable to deposit the check there, since the account would now be owned by the estate. Once there, the funds could only be withdrawn by the estate's legal representative, its executor or administrator.
BankingQuestions.com is a free service made possible by the generous support of our advertisers. Advertisers are not responsible for site content. Please help us keep BankingQuestions.com FREE by supporting our advertisers. When you see an ad for a product or service you may have an interest in, click through to learn more.