Singling out one day of the year for fasting, in celebration of Mawlid al-Nabi (the birth of Prophet Muhamamd), is an innovation (bid‘ah) that is contrary to the Sunnah of the Prophet. For more, see the detailed answer.

1. The biographers and historians differed concerning the day and month of the birth of the Prophet.
2. The strongest opinion concerning the birth of the Prophet (blessings and peace of Allah be upon him) is that he was born between the eighth and the twelfth of Rabee‘ al-Awwal in the Year of the Elephant.
3. The most well-known view is that the death of the Prophet occurred on 12th Rabee‘ al-Awwal 11 AH.

We do not know of any source for the hadith which reads: “Whoever offers congratulations to people for this blessed month (i.e. Rabi` al-Awwal), the Fire will be forbidden for him”, and it is clearly fabricated.

1- Celebrating Mawlid al-Nabi (Prophet Muhammad’s birthday) is an innovation.
2- Buying sweets on Mawlid al-Nabi comes under the heading of helping and propagating the celebration of Prophet Muhammad’s birthday; rather it is a kind of establishing that festival or ‘Eid. So it is better for you not to do that on the day of the celebration.

Exchanging visits and getting together on the ‘Eids and happy occasions, is something that brings happiness and increases love and strengthens the bonds between relatives. But what happens in many of these family gatherings, such as mixing between men and women, even if they are relatives and cousins, are bad customs that go against the teachings of the Quran and Sunnah.