Hi Carole,
Depends on what is meant by long term. With steroids, they boost the animal's appetite but can also depress them and reduce the immune system further. So if on steroids need to monitor his general health closely.
Fizz is only just 5. When diagnosed with FIV in Feb this year, he was chronically anaemic. He was on steroids from the end of January, 2 x 5mg prednicare steroids per day. Once his rbc was acceptable, we then weaned him off the tablets gradually as you can induce nasty side effects if you just stop them dead. He cam off them mid May.
Due to anaemia again, Fizz has been back on the steroids since 9th August. Again 2 per day but we are in the weaning off process.
I guess each case is very individual but, my thoughts are that I'd rather Fizz have a few quality years with the potential of losing him early, rather than him having miserable years - he really is such a lovely lively cat and seeing him run down with anaemia, no life in his eyes is too much to bear.
I hope you and your vet can sort out some kind of longterm help for Tabby.
Good news about the stools - sorry but I've no experience on this problem.