I am sure there is an official notice he must give you as well to start the legal process. He must feel that if you know he is going to eventually do that, maybe you'll just leave on your own.
This is AVVO, a place for users to obtain general legal information to general legal questions. I am glad to help you in any way I can, within those limits. I wish to make clear I am only communicating with you for the sole purpose of exchanging such general information, and nothing more. It is not legal advice, which I can not provide because among other reasons I know few of the necessary details of your situation. I do not purport to represent you in any way, shape or form. Of course, if you would like to seek out my services, and if you are a NY resident, I will probably not put up very much resistance but representation would still necessitate a signed retainer agreement between yourself and I. Thank you.
When a tenant (that's you) stays in a rental property after the expiration of a lease, the status of the relationship between the tenant and the landlord changes. Rather than being governed by a lease term, the term of the rental relationship become a continually renewable period based on when rent is paid. Generally, that period is one month for residential properties.
in this situation, most states require the landlord to give you official notice of the termination of the rental agreement at least one full rental cycle before you have to vacate. In your case, this would mean that your landlord would have to give you at least 30days notice of termination (provided there is nothing in IN law to the contrary). Whether or not a text message is sufficient to start the clock ticking, I don't know. However, a careful landlord would provide a written notice of the termination and mail it certified with delivery confirmation so that it can be shown to a court later if eviction action becomes necessary.
The safest bet for you is to contact a local attorney to discuss your specific options. If you don't want to go that route, then you should probably talk to your landlord directly about what the text message means and what your options are with the landlord. You should also start looking for alternative housing arrangements while exploring your options just in case you need to move in a few weeks.