Yes, the guy is 70, but I would not describe him as "in ill health" but rather plagued by spinal mechanical problems currently, which I'd point out didn't stop him filming a TV series last year. He's also lost between 4 and 5 stone through dieting, so apart from severe back pain is probably fitter than he's been for some years.
He'll probably never RUN onto a stage again, nor bounce up and down like he used to, but his band are certainly not a dying rock'n'roll band (and I suspect many would fiercely argue that Bruce Springsteen isn't either
, while the cast of the BOOH musical are still keeping Steinman's brand of rock'n'roll alive and taking it to a new generation). When he can get his back problem resolved Meat still wants to take to the stage with the NLE again, even if the long 3 plus months of touring may be over, and I believe he will still pack houses.
But Meat is far more than a rock'n'roll performer, he is an actor, and his career in acting is by no means ending. He is far from saying "thanks for the memories" .. just asking for some patience. He is a creative artist, and still planning ways of using that creativity to entertain
How much he will pack into 2018 I don't know, but he is by no means done.