A child can make an application to the court pursuant to Section 117 of the Succession Act 1965 for a share in the estate if it does not make proper provision for them. They must show that the deceased failed in their moral duty to make proper provision for the child. There are strict timelines for bringing a claim.
Section 117
There are a number of factors which can be considered by the court when deciding whether the deceased failed in their moral duty to make proper provision for the child including:

1. The amount left to the surviving spouse or the value of the legal right if the surviving spouse elects to take this,
2. The number of the testator’s children, their ages and their position in life at the date of the testator’s death.
3. The means of the testator.
4. The age of the child whose case is being considered and his or her financial position and prospects in life; and
5. Whether the testator has already in his lifetime made proper provision for this child.

Any child seeking to make a claim under Section 117 should try as best as possible to identify what if any monies he or she received from the deceased in the past.

A section 117 application is not available to a child where the deceased died without a Will