He had been unwell for a very long time.
Some 15 or so years ago I attended an Ice Cream conference and trade-show at some dreadful hotel in Blackpool. The place was well past it's best and there was a line of people at reception complaining about the gale blowing through their windows...
Apart from Conference delegates unfortunate enough to be staying there, it was busloads of blue-rinses. In the evening there was 'Special Guest Star' entertainment. Sid little alone ;-/
Eddie was quite unwell back then, too ill to travel or perform. Sid however had lost none of his professionalism or 'charm'. Sang, joked, regaled the audience with stories of their heyday. There was clearly a lot of affection for his ailing former partner. To be fair, he entertained the blue rinses who got their money's worth.
One forgets that in their day they were top of the bill. Those were different times.....