Have a read of this Liz. I would also suggest your son keeps his receipts to show his original journey and then the changes. Probably will never need them but always best to be on safe side.
You could also check with CA unit if you are really worried and would like to hear it from them.
Temp breaks in caring
You can still receive Carer's Allowance if you take a temporary break from caring, as follows:
â€¢if you go on holiday, or the person you care for has a holiday or a stay in a care home, your Carer's Allowance may be paid for up to four weeks in any 26 week period
â€¢if you receive treatment as an inpatient in a hospital or similar institution, your Carer's Allowance can be paid for up to 12 weeks in any 26 week period, depending on whether you have also had breaks from caring for other reasons
â€¢if the person you care for receives treatment as an inpatient in a hospital or similar institution, your Carer's Allowance can be paid for up to 12 weeks in any 26 week period
Your Carer's Allowance will stop if the person's Disability Living Allowance or Attendance Allowance stops. For adults, this is normally after they have been in hospital for four weeks.
The maximum break you can take without your Carer's Allowance being affected is 12 weeks in any 26 week period. You can get further advice about the rules from the Carer's Allowance Unit.