PIP award, ‘for an ongoing period’

I’m new to the benefits & work site. Would be very much obliged if anyone is able to assist. I’m a carer for my partner who has recently been awarded both daily living and mobility components at the enhanced rate. The decision letter is confusing to us as we are new to PIP and the benefit system minefield because it states that the award is for ‘an ongoing period’ but later in the letter it says ‘we will also contact you while you are getting PIP to see if you’re needs have changed and to look at the amount you get. This will be after 25 may 2031’. The awards for both components are from 25 may 2021. So it looks to us that the decision maker has awarded both for a full 10 year period. What we don’t understand is what DWP mean by (a) ‘for an ongoing period’ and (b) if my partner will be required to be reviewed after 25 may 2031? My partner is 52 years old
This is because medical evidence was supplied to show that his psychological and physical condition and disabilities are severe but are stable and are permanent and won’t improve, they will stay as they are if they do not deteriorate. His GP also wrote to DWP and their HCP to advise that his condition is such that it will make it distressing and harmful to his mental health if he were to be required to attend face to face assessments either in person or remotely. The DWP’s HCP recommended enhanced rate of both components and stated in report to DWP that ‘it is not appropriate to review the claim’. And went on to justify why. The report also says ‘it is likely that the functional restriction identified in this report will be present at the recommended point of review’. Additionally the HCP also said ‘The claimant has a mental, intellectual or cognitive impairment that may require additional support in order for them to comply with future claim processes’.
The DWP decision letter does not refer to a review and because of what their HCP included in the report, we are anxious for any assistance we can get regarding this because if there were to be future face to face reviews or even the need to make a new PIP application, it would cause a great deal harm and distress to my partners already very severe mental health.
I was even considering writing to DWP to request further information and clarification on the decision but thought I would run it past benefits and work and their members.
Finally I just want to say a massive thank you to benefits and work who’s information and the helpful members guides have been extremely helpful in assisting us with PIP claim. As I mentioned the benefit system is a minefield to us and the site and the information included helped immensely. Thanks in advance, Penny

Many thanks Catherine, that is very reassuring.
Your reply is greatly appreciated.