Assalamu alaykum. My father started to pray alhamdulillah. He knows nothing but Ikhlas so I'm guiding the prayer since he had struggles even remembering the number of rakaas and the words to say. Is the Salah accepted since I'm guiding and I'm a girl? Jazak Allahu khairan.
May Allah reward you both and increase you in guidance. There is an authentic hadith narrated by Imam Aḥmad, Abū Dawūd and others that mentions a woman named Umm Waraqa who was allowed by the Prophet 
to lead her family in prayer. The hadith in Abū Dawūd’s collection (vol 1, no. 218) mentions that there was an old man who gave the adhan and who presumably prayed behind her. Based on this hadith, some scholars permit women to lead men in prayer in times of necessity, for example when there is no man or boy who can do it out of a lack of knowledge.
Based on that hadith some scholars such as the 20th century Ḥanbalī scholar ʿAbd al-Raḥmān b. Qāsim say it is permitted for a woman to lead her family in prayer when it is necessary. Therefore what you are doing is acceptable according to their opinion until your father learns how to perform the prayer correctly.
Sources:
- ʿAbd al-Raḥmān b. Qāsim, Ḥashiyat al-Rawḍ al-Murabbaʿ, no publisher listed, 1397 AH (1976-1977 CE), vol. 2, 311.
I am surprised by how practical and flexible our faith is. I have a question, do you know the formation if the female lead the male in the prayer, while there is/are another female/s following the prayer? Thank you.
I haven’t seen anything specifically on that, but I would think they would follow the ordinary order of males before females.
Regards