In Jain philosophy, the terms are:

• Bhavya jiva – a soul that can attain moksha (liberation) one day.
• Abhavya jiva – a soul that can never attain moksha.

So, can a bhavya become abhavya?

No. According to Jain doctrine:

1. Bhavyatva / Abhavyatva is permanent

- A soul that is bhavya will always remain bhavya and will definitely attain moksha in some future birth. - A soul that is abhavya will never attain moksha, in any birth. ( jainknowledge.com)

1. We only don’t know which jiva is which

- Only a Kevali Bhagwan (omniscient being) truly knows who is bhavya and who is abhavya. - Ordinary people should never label anyone as abhavya; we should always assume everyone (including ourselves) is bhavya and keep trying for samyak darshan and moksha. ( jainknowledge.com)

1. Scriptural basis (simple)

- Jain texts (like Tattvartha Sutra) clearly state: “Some souls are bhavya and some are abhavya” – meaning these are two fixed classes of souls, not changing back and forth. ( jainknowledge.com)

So, in summary:

• Bhavya jiva cannot become abhavya.
• Abhavya jiva cannot become bhavya.

Their category is eternal; what changes is only our current state (with or without right faith), not the underlying capacity.

You can read more in simple language here and here .