aging dog vs. younger dog

Question
I HAVE 2 ENGLISH BULLS. MAX-MALE NUETERED 14 YRS OLD HAD SINCE HE WAS 8 MOS. ZELDA- FEMALE SPAYED 4 YRS OLD HAD SINCE SHE WAS 9 MOS. I GOT ZELDA ABOUT 6  MOS. AFTER LOSING MY FIRST BULLIE SHE PASSED AWAY VERY SUDDENLY AFTER A BRIEF ILLNESS AND SWORE I WOULD NEVER HAVE TWO DOGS AGAIN BECAUSE OF THE GRIEVING THAT MAX WENT THRU. UNTIL ...ZELDA A FRIEND GAVE HER TO ME SUGGESTING IT WOULD BE GOOD FOR ALL OF US...AND IT HAS BEEN. THEY HAVE SHARED EVERYTHING AND GOT ALONG WONDERFULLY UNTIL ABOUT SIX MOS.AGO MAX STARTED GETTING GROUCHY.SO AT NIGHT I WOULD SEPARATE. THEN THE AGGRESSION STARTED WHEN THEY WOULD BE LEFT ALONE,TO THE POINT THAT ZELDA GOT HIM PRETTY GOOD.DONT KNOW WHO STARTED IT. SO THEN I HAD TO SEPARATE WHEN IM NOT HOME.NOW ITS GETTING MUCH WORSE,THE AGRESSION HAS STARTED AT ALL HOURS OF THE DAY,DIFFERENT PARTS OF THE HOUSE AND THEY BOTH ARE STARTING IT.I HADNT MADE ANY CHANGES IN THE WAY THEY WERE TREATED OR SPOILED,THESE DOGS HAVE PRETTY MUCH BEEN OUR KIDS,THEY USED SLEEP NEXT TO EACHOTHER,GO ONE WALKS TOGETHER,THE GROOMERS ETC. NOW I CANT EVEN HAVE THEM IN THE SAME ROOM.  HELP... I WANT SOME KIND OF PEACEFULNESS FOR MAX,(AND MYSELF)AND I DONT WANT ZELDA DEVELOPING BAD HABITS THAT LEAD TO TROUBLE WITH OTHER DOGS.

Answer
The first thing I'd do would be to take Max to the vet. It could be that he may have something physically ailing him, and Zelda is picking up on it and responding with aggression. In the wild, an aging and/or sick individual would be driven out of the pack. That could be what Zelda is trying to do. Or, it could be that Max is in pain and that is causing his grouchiness towards Zelda. Either way, a vet check is in order for Max.

In the meantime, I would keep the two of them separated whenever you cannot supervise, and immediately correct any signs of aggression out of either one of them, whenever you are at home and they are together. That might mean that you have to keep Zelda on a leash, so that you can back Max up if he tells her he doesn't want to be bothered and, instead of leaving him alone, she decides to go after him.

I would also recommend that you try and find a local trainer that can come to your house, who has experience dealing with dog-to-dog aggression. Without being there and seeing exactly what is going on, it's very difficult to give advice in situations like this. It could be that Max is actually starting the fights, but because Zelda is younger and stronger, he is the one who ends up suffering the consequences. I cannot give accurate advice without being there to see them.