I’ve not seen any posts on here with tracked vehicles. But they all work the same way, the have a SIM and upload the journeys. It is a 3rd party company that does it and most likely Motability will only look at it once a week.
If you are visiting your brother 2 or 3 time s aweek, I cant see that being a problem as you are looking after his needs. It may be that your brother is staying with you for a few days a week. the tracker cannot account for that. All it will see is 2 visits to your brother in a week.
As above, It is only for extreme cases will they do anything.