Well now I have a 7yo tb, but my first horse was at the time 22, and she passed peacefully this april just gone at a ripe old age of 25, and up until the very last ride and show she still jumped her heart out which is what she loved doing the most of all, unfortunately her heart gave out when she got cast in a paddock and the winter weather did the rest.
I do have to say though, well done for even having a 28yo tb, to me that's pretty amazing as I was looked at in a very dumbfounded expression when I told the vet my girl was 25, not 10. She was only 15.2hh though.
-Just prepare for the worst though, as if he does go downhill it'll hit you when you least expect it, Bubbles was in the front paddock one school morning, I really didnt expect her to go so quickly, but for her sake I'm glad she did. There was no fighting.
Is he the one in your dp?
R.I.P ~ Bubbles - 25yo tb mare - 13.04.2011 ~ 8:30am ~ passed away naturally and peacefully in my arms