He has three wives and his family need him to be present among them, but he is intending to observe i‘tikaaf for the entire month of Ramadan!

i‘tikaaf is an important act of worship in
which a person cut himself off from worldly distractions in order to check
himself and worship his Lord. Whatever he could not do before that, he is
freeing up his time to do now, and whatever he was falling short in before
that, he will now be able to give it the time it deserves. There is no
difference of opinion among the scholars concerning the fact that it is
Sunnah. In al-Fath al-Baari (4/272), al-Haafiz Ibn Hajar quoted Imam
Ahmad as saying: “I do not know of anyone among the scholars who differed
concerning the fact that it is Sunnah.” But this act of worship is not
permissible if it will lead to falling short in a shar‘i obligation such as
looking after one’s family, taking care of one’s sick wife, and looking
after one’s father and mother, if a person is the only one who can take care
of that and there is no one else who can take his place. Although it is
possible for some of his brothers and sisters to look after his parents,
there is no one else who can take care of his children or his wives except
him. 

Therefore, based on what is mentioned in the
question, we do not think that it is permissible for the husband to observe
i‘tikaaf for the entire month, or even for less than a month, because as a
result of that he will neglect his duties as prescribed in Islam and as
enjoined by his Lord, may He be exalted, upon him. 

We think that it may be possible to combine
the two matters, by taking care of his family and meeting their needs, then
going into i‘tikaaf for a few days, then he can go back to his home and do
what Allah has enjoined upon him, then go back into i‘tikaaf again. In this
manner he will avoid going against Islamic teachings and no one will be able
to blame him in any way. 

Shaykh ‘Abdullah ibn Jibreen (may Allah have
mercy on him) was asked: 

What is the maximum and minimum length of
i‘tikaaf? 

He replied: 

There is no maximum limit, but it is
disliked (makrooh) to make it lengthy if that will lead to the person
neglecting his family and being distracted from them. It is narrated in the
hadeeth: “It is sufficient sin for a man to neglect those for whom he is
responsible.” The one who makes it very lengthy will inevitably be
neglecting the pursuit of his livelihood and will be burdening others with
the responsibility of spending on him, and will cause them hardship because
they will have to bring him his food and drink in the mosque, and so on. 

Hiwaar fi al-I‘tikaaf,
question no. 2 

He (may Allah have mercy on him) was also
asked: 

If a person wants to do i‘tikaaf but he is
in charge of his house and there is no one else, then which is better: to
take care of the members of his family or to do i‘tikaaf in the mosque
during the last ten days of Ramadan? 

He replied: 

We prefer that he should undertake his duty
towards his family, meet their needs and stay with them as a mahram and
companion, and to protect them, take care of their household, and earn a
living with which to provide for them. If he goes into i‘tikaaf and leaves
them without any guardian, they will be exposed to the dangers of thieves
and evildoers, or not having their needs met, or having to go to the trouble
of bringing their own goods from the market, or burdening others with having
to buy what they need, which may lead to reminders of their favours that
cannot be tolerated. Muslim narrated that ‘Abdullah ibn ‘Umar said: The
Messenger of Allah (blessings and peace of Allah be upon him) said: “It is
sufficient sin for a man to neglect those for whom he is responsible (for
their provision).” 

That also includes not spending on them and
neglecting them by not earning a livelihood when one is able to do so. If
there is someone and his relatives can look after their needs and protect
them and bring them what they need, then it is permissible to do i‘tikaaf 
and in fact it is mustahabb, because there is nothing to distract one from
it. 

Hiwaar fi al-I‘tikaaf,
question no. 11 

You can see the entire essay (in Arabic) via
the following link:

http://ibn-jebreen.com/book.php?cat=3&book=10&toc=328 

We have previously pointed out the error
made by some people who are distracted from looking after their families and
taking care of their affairs on the grounds of focusing on da‘wah or
teaching. That is not a valid excuse for them to neglect that which was made
obligatory upon them. For more information, please see the answers to
questions no. 3043, 6913,
23481 and 110591. 

And Allah knows best.