To expand a little on my earlier answer, the court will sentence him when the court is ready. There is no mileage for them to continually postpone sentencing but they will not do so until everything that needs to be done has been done. He should ask his lawyer the reason for the delay as nobody here can do other than guess why it might be.
Just a few comments on the likely sentence. The Sentencing Guidelines do NOT provide a suspended sentence as a specific recommendation. The process is that the sentencer (be it judge or Magistrates) determines whether a custodial sentence is necessary. Then the length of that sentence is decided. Then, and only then, is consideration given to suspending the sentence. Whether it is suspended depends on a number of factors but the offender’s previous record is a big determinant as is the nature and seriousness of the offence. The maximum sentence that can be suspended is one of two years and the maximum suspension period is two years.
Looking at the specific offence of theft, offences are put into categories of seriousness based on the value of the items stolen. £50,000 is in the middle of Category 2 which covers from £10k to £100k. The suggested sentencing range for such an offence is from a Community Order up to three years custody and it is impossible to be more specific as the factors which influence sentencing are many. In particular it may be considered more serious in view of the fact that the victim was the offender’s parents. This would not automatically be seen as “in breach of trust” as suggested by Eddie (depending from where and how the money was stolen) but stealing from one’s parents increases the seriousness considerably as parents should be able to trust their children - however old they may be - not to steal from them.
Once again, nobody here can do anything but guess what a likely sentence will be but he should not rely on any prison sentence being automatically suspended.