She had an operation and offered several prayers without having purified herself and without facing the qiblah

Firstly: 

When a sick
person wakes up from the anaesthetic, he has to make up the prayers that he
missed for that reason.

 Secondly: 

If a sick
person is unable to do wudoo’ and there is no one who can help him do
wudoo’, then he should do tayammum, even if he strikes his hands against a
wall or piece of furniture if there is dust on it, or he may bring some dirt
with him with which to do tayammum. If he is unable to do tayammum then he
may pray as he is. 

The same
applies with regard to facing the qiblah and covering the ‘awrah (wearing a
khimaar or head cover). If he is able to do any of that then he must do it,
but whatever he is unable to do is waived for him and he is not accountable
for it, because Allaah says (interpretation of the meaning): 

“Allaah
burdens not a person beyond his scope”

[al-Baqarah 2:286]

Shaykh Ibn
‘Uthaymeen (may Allaah have mercy on him) was asked: If a sick person cannot
find any dust, can he do tayammum using the walls or furniture, or not? 

He replied:
The walls come under the heading of clean earth, so if the walls are built
of clean earth, whether that is stones or clay bricks, then it is
permissible to do tayammum using them. But if the walls are covered with
wood or paint, if there is dust on it they may be used for tayammum and
there is nothing wrong with that because then he will be like one who does
tayammum on the earth, because dust comes from the earth, but if there is no
dust on it, then it does not come under the heading of clean earth, so he
should not use it for tayammum. 

With regard
to furniture we say: if there is dust on it he may use it for tayammum
otherwise he should not do tayammum on it, because it does not come under
the heading of clean earth. End quote from Fataawa al-Tahaarah (p.
240). 

The Standing
Committee for Issuing Fatwas was asked: I am bedridden and cannot move. How
can I purify myself in order to pray, and how can I pray? 

They
replied: Firstly: with regard to purification, the Muslim must purify
himself with water; if he is unable to use it because he is sick or for some
other reason, he may do tayammum with clean earth. If he is unable to do
that then the requirement to purify himself is waived and he should pray as
he is. Allaah says (interpretation of the meaning): 

“So keep
your duty to Allaah and fear Him as much as you can”

[al-Taghaabun 64:16]

“and
[Allaah] has not laid upon you in religion any hardship”

[al-Hajj
22:78]

With regard
to urine and faeces, it is sufficient to clean it with stones (istijmaar) or
clean tissues with which the place where it comes out should be wiped three
times or more, until the place is clean. 

Secondly: 

With regard
to prayer, the sick person has to pray standing. If he cannot pray standing,
then sitting, and if he cannot sit, then on his side, because of the report
from ‘Imraan ibn Husayn, that the Prophet (peace and blessings of
Allaah be upon him) said: “Pray standing, and if you cannot then sitting,
and if you cannot then on your side.” And Allaah says (interpretation of the
meaning): “So keep your duty to Allaah and fear Him as much as you
can”[al-Taghaabun 64:16]. End quote from al-Fataawa al-Muta’alliqah
bi’l-Tibb wa Ahkaam al-Marda, p. 78. 

Thirdly: 

If you
prayed as you described, without wudoo’ or tayammum, and without facing the
qiblah, and without wearing the khimaar because you were unable to do that,
and because there was no one to help you do wudoo’ or tayammum or to make
you face the qiblah, then your prayer is valid and you do not have to repeat
it. 

If it was
possible for you to do tayammum or wudoo’ with the help of another person,
but you failed to ask for help, then you have fallen short in seeking to
purify yourself, which is a condition of the prayer being valid, and you
have to repeat the prayers that you offered when you were not pure and did
not face the qiblah. 

Fourthly: 

The prayers
must be repeated immediately, if you are able, as soon as you come to know
that repeating them is obligatory. You should start with the prayer that you
missed, and offer them in order with the proper intention, and pray ‘Isha’
for the first day, then Fajr, Zuhr, ‘Asr, Maghrib and ‘Isha’ for the second
day.  

What is
meant is that you should do that in one go, if possible, whether that is in
the morning or at noontime or at whatever time of day you come to know of
the ruling that they must be repeated. It is not permissible to delay the
prayers and make them up at separate times, as some people think. 

If making
them up in one go is too difficult for you, then you should pray whatever
you can, then rest, then finish making up whatever prayers you owe. 

Shaykh Ibn
‘Uthaymeen (may Allaah have mercy on him) was asked about a sick person who
had surgery and missed a number of obligatory prayers. Should he pray them
all together after he recovers, or should he pray each one at its proper
time, such as praying Zuhr with Zuhr and so on? 

He replied: 

He should
offer them all together in one go, because when the Prophet (peace and
blessings of Allaah be upon him) missed ‘Asr during the battle of
al-Khandaq, he prayed it before praying Maghrib. If a person misses some
obligatory prayers he must pray them all together and not delay them. End
quote from Majmoo’ Fataawa Ibn ‘Uthaymeen (12/222). 

And Allaah
knows best.