She prayed naafil after Fajr and it was said to her that this puts one beyond the pale of Islam

Firstly: 

One of the
greatest acts of worship that a Muslim can do and draw close to Allaah is
prayer. The Prophet (peace and blessings of Allaah be upon him) said:
“Prayer is the best thing prescribed, so whoever can do a great deal of it,
let him do that.” Narrated by al-Tabaraani and classed as hasan by
al-Albaani in Saheeh al-Jaami’ (3870). 

But the
Prophet (peace and blessings of Allaah be upon him) forbade us to offer
naafil prayers at certain times. For more details please see the answer to
question no. 20013. 

These times
include the period from after Fajr prayer until the sun has risen and become
high, which is until approximately fifteen minutes after sunrise. 

In Saheeh
Muslim (832) it is narrated that the Prophet (peace and blessings
of Allaah be upon him) said to ‘Amr ibn ‘Abasah (may Allaah be pleased with
him): “Pray Fajr, then refrain from praying until the sun has risen and
become high”. The prayer that is forbidden at these times is naafil prayer
for which there is no reason, which the scholars call al-nafl al-mutlaq
(general naafil prayer), such as that which is mentioned in the question,
where a person stands and offers a voluntary prayer to Allaah after Fajr.
This kind of prayer is disallowed (at this time). 

As for
prayers for which there is a reason, such as greeting the mosque, the Sunnah
prayer after wudoo’, two rak’ahs following tawaaf and so on, these may be
done when the reason for them is present, even if that is at a time when
other naafil prayers are forbidden. See the answer to question no.
306. 

Secondly: 

As for your
friend’s saying that praying at this time puts one beyond the pale of Islam,
this is not correct, and it is speaking about Allaah without knowledge. It
is not permissible for anyone to say anything about the religion of Allaah
that he does not know. Allaah says (interpretation of the meaning): 

“Say (O
Muhammad): (But) the things that my Lord has indeed forbidden are
Al‑Fawaahish (great evil sins and every kind of unlawful sexual intercourse)
whether committed openly or secretly, sins (of all kinds), unrighteous
oppression, joining partners (in worship) with Allaah for which He has given
no authority, and saying things about Allaah of which you have no knowledge”

[al-A’raaf 7:33]

So she has
to repent to Allaah. 

Offering
naafil prayers at this time is not allowed, and the one who does that is
sinning, because he is doing something that the Prophet (peace and
blessings of Allaah be upon him) forbade, but that is not kufr as your
friend claims. 

And Allaah
knows best.