I agree that getting him neutered is your first step. Even though he is difficult to handle, if he will go into a carrier you can get him to the vet to be neutered - just be sure to let the staff there know the situation so they will know how best to handle him.
You may actually want to keep a carrier in his room if you don't already. Most cats like having a place to retreat to and it would be preferable (from your standpoint) for him to be running into a carrier to always running under the bed (you may also want to check to make sure he is not urinating under the bed). To encourage him to use the carrier you can put treats in there (or even his regular food) so that he relates it to a good experience.
As others have mentioned you should continue using the same litter and litterbox type that Aldo is used to, but you can mix the Cat Attract (I am assuming that is the litter you are talking about) in with it to encourage him to use his box.
As for getting him to start accepting him, you are on the right track - continue to sit in the room with him and read out loud or just talk to him. You can also try to engage him with a wand toy - often cats become so engrossed in the chase that they don't mind if you happen to touch/pet them as they run by, and will jump in your lap without second thought as they try to grab the elusive toy. Avoid eye contact at this stage as this can be perceived as a challenge, but blinking slowly then turning your head away is kitty talk for acceptance of him.
Bottom line - patience will be your most effective tool - give him time to adjust, accept, and feel comfortable in his new home. A week may seem a long time to you, but it may take many more weeks, or even months before he fully accepts being in his new home. You may consider introducing him to your other cats before that happens, but if you do just realize that he may bond to them instead of you, in which case you may never win him over. If he has been around dogs before, you can introduce him to yours any time after he has met the other cats, but if not he may need even more time to accept that a dog can be a friend rather than a foe.
You may actually want to keep a carrier in his room if you don't already. Most cats like having a place to retreat to and it would be preferable (from your standpoint) for him to be running into a carrier to always running under the bed (you may also want to check to make sure he is not urinating under the bed). To encourage him to use the carrier you can put treats in there (or even his regular food) so that he relates it to a good experience.
As others have mentioned you should continue using the same litter and litterbox type that Aldo is used to, but you can mix the Cat Attract (I am assuming that is the litter you are talking about) in with it to encourage him to use his box.
As for getting him to start accepting him, you are on the right track - continue to sit in the room with him and read out loud or just talk to him. You can also try to engage him with a wand toy - often cats become so engrossed in the chase that they don't mind if you happen to touch/pet them as they run by, and will jump in your lap without second thought as they try to grab the elusive toy. Avoid eye contact at this stage as this can be perceived as a challenge, but blinking slowly then turning your head away is kitty talk for acceptance of him.
Bottom line - patience will be your most effective tool - give him time to adjust, accept, and feel comfortable in his new home. A week may seem a long time to you, but it may take many more weeks, or even months before he fully accepts being in his new home. You may consider introducing him to your other cats before that happens, but if you do just realize that he may bond to them instead of you, in which case you may never win him over. If he has been around dogs before, you can introduce him to yours any time after he has met the other cats, but if not he may need even more time to accept that a dog can be a friend rather than a foe.
