Impact of Pension on Benefits

Hi to all.
My husband is just 64 couple of weeks ago.
He had his PIP done last year and had to go to tribunal to get it though, even with the help of our Social Services lady!
He got higher rate of both until the year 2027! So with him being 65 next Feb will this mean it will stop? He claims ESA for us both, as I'm not allowed to claim it because we are married, but what will happen to out money then? we get the severe allowance on top of this as well, for me and my husband.
I have no idea how the DWP works with benefits as before i became ill myself had never claimed anything ever!
I'm still on DLA at the moment, and am dreading going to pip, as i had to fight for DLA and go to court, but was awarded it for life in the end, although i know that makes no difference to a pip assessment. Both my husband and i have a private carer that comes in 26hrs per week to help so i know we are lucky trust me.
The other thing on my mind is the fact that a few years ago my husband got a pension from the forces, it was started in 2014 with a lump sum of £8,500 and then different amounts over the last 4 yrs.
We have just been in touch with DWP and they are not happy at all, they told us we needed to have told them about it and we said nothing, as we didn't know that we had to tell them...........
As we have a financial assessment every year because we have a carer and Adult social services and us pay for it. we signed a letter to ''share'' all information about our monies etc, and even the tax people knew we had it, but this was not shred with the DWP, so now they have asked for 4 years bank statements, and and proof of what we spent the money on?? even though this is near;y 4 yrs later.
We then got a payment of ESA and they had started to take £150 every 2 weeks from us with not letter no warning and that's almost £300 per four weeks we are down. ( and yes finding it hard) and we still have no reason why? how much? how long? and what we owe? I know we are aloud to have some savings but i don't know how much, i have provided all i can from 4 yrs ago, but can only give the proof of £4, 800 as to where it was spent, but surly we are able to count some of this as savings? As i say i don't know about the claims with DWP my husband knows more than me..I really don't know if I'm coming or going, we are honest nice people and would never dream of fraud or anything like it, so i guess i have many questions with this message, maybe there's someone out there who could give some advice??
DWP have had the information since the 6th Jan and still no letter or anything i think that's so bad i really do, they could at least send a note to say what's what?
So if anyone can shed any light for me then that would be wonderful, i just seem to worry all the time, and have had to consolidate all our payments into a large loan from the bank payable over 2 yrs at £400 a month. (£9,400) total. thanks for reading this and any help would be great thanks. I have Lupus and many other things and so dose my husband.