I would advise
against it for a few reasons. One is that he is quite old already and adding a new rabbit will be stressful. Even if all were to go well, there would still be an amount of stress that may be nothing for younger rabbits but may be a bit much for an elderly rabbit.
Two is that it isn't advised to introduce a baby to an adult. Yes, they will likely get along -- but only for a short time. As soon as the young one's hormones kick in, it can alter the behavior of either (or both) rabbits.
Three, those hormones could cause either or both to
physically fight. For a 10 year old to have to deal with that wouldn't be good.
In my opinion, he's a bit old to put him through a bonding process. If you wanted to find him a bondmate, I'd let him meet some already fixed rabbits to pre-screen for potential compatibility. Perhaps you could even find an older one. If it were a younger, fixed rabbit, just bear in mind that as soon as your current old boy passes, the younger bondmate will be left to deal with his loss and be left alone (until you then get another one to bond with him and go through the bonding process all over again).
