It's a well known side effect of NOT diabetes itself BUT of long term higher blood glucose levels than people without diabetes - often one of the natural side effects of just getting older. I remember by late mum-in-law (my mum was already deceased by then, being older than MIL was when I was born, than MIL was when she had my husband) telling us 2 that 'Old age doesn't come on its own, y'know!' when we were 50-ish and already knew that fact .......
Seriously, from a diabetes point of view - about the only thing you can do is try and minimise the times your blood glucose IS higher than 'normal' - and you may see some improvement in this area, as well as generally - but no guarantees it'll help or not. Certainly won't be very quickly, anyway.
There are other things that might help - but much like Viagra/sildenafil pills - it always does make the sex act less spontaneous or automatic.
By the way - even at your own advanced age (said kindly, cos I'm the same age as you - and my husband is older than you and also has ED which can't be cured or improved cos his was caused by a prostatectomy) and he's tried a few things for his - you still ought to check out whether you have a problem with your prostate by having a simple blood test - as should any man when he gets to age 50, if not younger. If you don't wish to involve your own GP you can get that done (not free though) via the website
https://www.mypsatests.org.uk/ and then clicking on the 'Events' tab and seeing whether there's one near enough to where you are, or sending for one of their home tests. Their website gives loads of info about that bit of you, if you want it.
