Is my dad elgible for early release because he is disabled

Early release from where? Jail? Prison? What was his crime and what is his sentence? What is his disability? And lastly, what is his location?

We need details to help you properly.

No, if this is prison, if seriously disabled, most states (in America) has special housing units. A disability gives them no special privileges.

Where I am it can get you release and an ankle monitor. Something your lawyer needs to fight for. No guarantees, because it depends on at least a dozen factors, some stated above.

Again, this will depend on whether this is jail or prison. Prisons have accommodations for people with disabilities where most smaller local jails do not.