Joint tenancy

Joint tenancy is a form of co-ownership in which two or more persons, often husband and wife, own property in equal individual interests. Right of survivorship is the key feature of a joint tenancy. A deceased joint tenant’s interest vests in the surviving joint tenant at the moment of death, without requiring probate administration. The interest vests by reason of the nature of the title and, therefore, is not subject to disposition by the deceased joint tenant’s will.

In joint tenancy, each joint owner has an undivided interest in the entire property. If one joint owner passes away, their interest automatically transfers to the surviving joint owners, and this process continues until only one owner remains.

Therefore if you apprehend any such issues in future, you can purchase the property under joint  tenancy also.

But remember that his share in the property cannot be claimed by anyone after his lifetime except his own class I legal heirs. 

As joint owner you have purchased the property or inducted as "tenant" in the property, since law differ in both situations.

Be clear in your post.

It will be complicated otherwise , however you can settle the apprehensions by making some documents like will dee, t family settlement  agreement or simply create a trust for the property with beneficiaries.

Agree with will deed or family settlement agreement