If her father dies intestate, yes she is eligible for a share.

The individual, who convert himself to other religion from Hinduism, will not forego the right of any inheritance.

The bar for inheritance is only in respect of legal heirs of the convert.

Your sister is descendent of Hindu family, therefore her right as one of the heirs can not be denied to her even if he has converted………….

The children of the convert and their descendants can also get over the disqualification if they reconvert to Hinduism at the time the succession opens.

Central Government Act

Section 26 in The Hindu Succession Act, 1956

26. Converts descendants disqualified. Where, before or after the commencement of this Act, a Hindu has ceased or ceases to be a Hindu by conversion to another religion, children born to him or her after such conversion and their descendants shall be disqualified from inheriting the property of any of their Hindu relatives, unless such children or descendants are Hindus at the time when the succession opens.

Section 2 in The Hindu Succession Act, 1956

2.

(1) Application of Act. This Act applies-

(a) to any person, who is a Hindu by religion in any of its forms

(c) any person who is a convert or reconvert to the Hindu, Buddhist, Jaina or Sikh religion.

(3) The expression" Hindu" in any portion of this Act shall be construed as if it included a person who, though not a Hindu by religion, is, nevertheless, a person to whom this Act applies by virtue of the provisions contained in this section.

You may also go thru the judgment delivered by

Madras

High Court

E. Ramesh And Anr. vs P. Rajini And 2 Ors

https://www.indiankanoon.org/doc/346973/

6. (i) Whether the Hindu, by conversion, can forego the right of inheritance?

7. So far as the first question is concerned, the learned single Judge referred to Section 26 of the Hindu Succession Act (hereinafter referred to as the Act) and held that the bar for inheritance is only in respect of legal heirs of the convert. The individual, who convert himself to other religion from Hinduism, will not forego the right of any inheritance. He also relied upon the judgment in the case of Asoke Naidu v. Raymond S. Mulu,

9…………………Section 28 of the present Act discards almost all the grounds which imposed exclusion from inheritance andlays down that no person shall be disqualified from succeeding to any property on the ground of any disease, defect or deformity. It also rules out disqualification on any ground whatsoever excepting those expressly recognized by any provisions of the Act.

12…………………….Caste Disabilities Removal Act, 1850 (Act 21 of 1850) had not been repealed so far. This Act contains only one Section, which is as follows :

"Law or usage which inflicts forfeiture of, or affects, rights on change of religion or loss of caste to cease to be enforced ; So much of any law or usage now in force within India as inflicts on any person forfeiture of rights or property, or may be held in any way to impair to affect any right of inheritance, by reason of his or her renouncing, or having excluded from the communion of, any religion, or being deprived of caste, shall

cease to be enforced as law in any Court."

13. This enactment removed the stigma to inherit the property, in case of conversion to other religion. By virtue of this provision, definitely, the conversion of a Hindu to other religion will not disentitle the convert from...(sic) his right of inheritance to the property.

You may also go thru:

Andhra High Court

Shabana Khan vs D.B. Sulochana And Ors. on 24 September, 2007

https://indiankanoon.org/doc/1100051/?type=print

and another thread:

https://www.lawyersclubindia.com/forum/Section-26-hindu-succession-act-88836.asp#.UybYukeBmXU

well advised by experts

In so for as ancestral property is concerned, she is entitled for equal share as her siblings.

Even in case of conversion of religion, her rights over the ancestral property will not diminish for any cause.