Salaah

Q: In Saheeh Muslim there is a hadeeth in the chapter of forgetting in salaah. The hadeeth mentions that after the salaah wherein Rasool (Sallallahu Alayhi Wasallam) performed three rakaats in salaatul Asr, Rasool (Sallallahu Alayhi Wasallam) entered his home and came back out and spoke etc. and then just made sajda sahw.

1. People now say that if one begins to talk after the salaah wherein sajda sahw supposed to take place, he has to repeat the entire salaah. Please explain.
2. The hadeeth mentions that Rasool (Sallallahu Alayhi Wasallam) came out angrily. Why did he become angry?

Q: While performing four rakaats sunnat salaah, I mistakenly made one salaam after two rakaats. Realizing my mistake, I immediately got up and completed the remaining two rakaats and made sajda-e-sahw. Is this acceptable or do I need to repeat the salaah?

Q: What do the four madhabs say regarding congregational salaah for men? Do they say it is wajib or only mustahab? Can you cite references in your answer?

Q: My grandfather has alzheimer's. He forgets everything. He even does not remember how to perform Salaah. What is the mas'alah in this case? When ever we at home we make jammat for salaah so that he can perform his salaah but he even speaks in salaah.

Q: If I enter the musjid and join the salaah while the Imam is in ruku, then after saying the takbeer, should I go straight into ruku or should I first recite the sana? If I should not recite the sana before going into ruku, then when should I recite it?

Q: Is it preferable for the Imam to lengthen the Ruku' briefly when hearing someone entering the Masjid to join the Salaah?

Q: I visited a certain website, according to them hanafis can't pray behind Imams of the haramain if they don't take care of the masaail in wudu as hanafis do i.e they should do masah of head to more than quarter of the head, if they don't do we can't pray behind them. I think this is not good, at the time of Sahaba there would not have been such an issue as to not offer salah behind any specific sahabi. Please clarify.

Q: If a person forgets to make Sajda Sahw and has made both Salaams can he still make the Sajda Sahw and does he repeat Attahiyaat, Durud and dua after Durood?

Q:

1. List the circumstances under which an Imam who is the most knowledgeable may in his own presence permit a man of lesser knowlege to be Imam for that Salaah; meaning that how is it possible for an Aalim to permit a hafiz to be Imam when the more knowledgeable person has the responsibility by virtue of his greater knowledge to correctly be the appropriate Imam?
2. Does the Imaamat of the unappointed Imaam, despite it being out of place, does the Salaah of such an Imaam and that of those musallees following such an unappointed Imaam, become an invalid or null and void Salaah?

Q: The Imaam of my Musjid trims his beard to less than a fist length. Should I pray salah after him or not?