Answer
Wa `alaykum as-Salaamu, wa Ramatullahi wa-Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- If the pension is given by a party, whereby your father did not own the contributed money, then your mother, as assigned beneficiary, is alone the person who has the right to this pension.
2- If your father owned the money in that account, from which the pension accrued, and he was able to select the kind of investment in it, then your half-brother has a right in it.
In his response to your question, Prof. Dr. Monzer Kahf, Professor of Islamic Finance and Economics at Qatar Faculty of Islamic Studies, states:
Pension that is based on past contributions during employment and given according to acturial systems is not inheritance and it is permissible to pass, after death to a beneficiary that is determined according to the insurance system that is either created by law or by contract (it can even be with an insurance company based on a term life insurance).
On the other hand, a pension that is based on savings during lifetime, whereby a person saves money in a certain account like IRA or 401K in the US, and the contributor is the owner of these savings during lifetime, whatever balance in that account and to anyway it may be converted upon death (like converting it to a pension to a certain beneficiary) must be distributed according to inheritance law.
Accordingly, if the pension you mentioned is given by a party, whereby your father did not own the contributed money, then your mother, as assigned beneficiary, is alone the person who has the right to this pension. But if your father owned the money in that account, from which the pension accrued, and he was able to select the kind of investment in it, then your half-brother has a right in it.
Almighty Allah knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.