Time limit for challenging a will in Texas?
"After a will has been admitted to probate, any interested person may institute suit in the proper court to contest the validity thereof, within two years after such will shall have been admitted to probate, and not afterward, except that any interested person may institute suit in the proper court to cancel a will for forgery or other fraud within two years after the discovery of such forgery or fraud, and not afterward. Provided, however, that incapacitated persons shall have two years after the removal of their disabilities within which to institute such contest."
Note that the statute does provide a discovery rule exception for forgery or fraud. Texas Will Contest Law Firm