Reports say dying Libyan jailed for 1988 attack could be freed next week.
She said his condition was “very grave” and that he was “very weak, he is suffering from severe pain and he is in distress”.
Some relatives of the victims have said the dropping of the appeal means that a number of questions over the bombing could now go unanswered.
Speaking to Al Jazeera, Pamela Dix, whose brother Peter was killed on Pan Am Flight 103, said: “My immediate sense is that this is the worst possible outcome that we could have at this time.
“Al-Megrahi protests his innocence and the Scottish appeal court has said there may be grounds for a miscarriage of justice, but we now will not see the examination of that evidence in a courtroom so it’s an eminently unsatisfactory position from my point of view.
“What I would wish to see happen now is that the UK authorities grant that full independent inquiry that they have denied us, not least because they thought it would prejudice the criminal inquiry.
“Now there is no criminal process let us see what they are prepared to do.”
Lord Arthur Hamilton, Scotland’s most senior judge, said he had accepted al-Megrahi’s request to withdraw his long-standing appeal, but said there were other legal hurdles to be negotiated before the appeal process could be completely closed.
The court is expected to meet again in three weeks’ time to finalise the process, which depends on Scotland’s judicial authorities dropping their own appeal against al-Megrahi’s original sentence, which they saw as too lenient.
Last week, reports suggested he could be released on compassionate grounds within a week, although Scottish authorities have not confirmed this.
The latest developments have also sparked concern in the United States, where politicians and victims’ families are urging Scotland to keep al-Megrahi behind bars.
|Clinton is pushing for the Scottish authorities to make al-Megrahi serve out his sentence [EPA]
Hillary Clinton, the US secretary of state, is pushing for the Scottish authorities to make al-Megrahi serve out his 27-year sentence.
Seven US senators, including Edward Kennedy and John Kennedy, have also written to Kenny MacAskill, the Scottish justice minister, with a similar request.
The development comes after reports that the former Libyan agent could be granted an early release from prison by next week.
Al-Megrahi, who has repeatedly protested his innocence, lost an appeal in 2002 and last year failed to secure his release on the grounds he was dying.
In May this year, his lawyers began an appeal against his conviction at a court in Edinburgh, saying the case against him was flawed.
Libya has been making progress towards shedding its pariah status in the West and the release would mark an important milestone in its reintegration into the international community.
Under a transfer agreement signed between Libya and Britain, al-Megrahi could be sent back to Libya to serve the remainder of his minimum 27-year jail sentence.
Libya accepted responsibility in 2005 for the Lockerbie bombing and said it would pay about $2.7bn in compensation to the families of those killed in the attack.
That move prompted the lifting of international sanctions against Libya and led to a restoration in diplomatic ties between Tripoli and the West.