attacking

Question
I will forwarn you this is a long history.  I rescued my Maltese, Fred ~ 5 years ago.  He is currently 12 years old.  When I rescued him, he had many health problems & has subsequently had all of his teeth pulled, had a rectal hernia repair & has had a multitude of "warts" removed due to his chewing on them.  He failed to stud with another dog & I later found out after he was returned to his owner (who was upset because they did not get to collect their stud fee) the owner locked him in a garage & "walked away."  The individual who's female he was to stud with discovered this & "stole" him from the owner & he was my dog ~ 1 week later.  When I got him, he weighed ~ 7# (he currently is a healthy 12#).  I was out of town the evening he was delivered.  So, his first night was spent with my roommate, although he is my dog.  My roommate also has a Maltese (female ~ 2 1/2 years old) & we are to soon be given my Mother's 6 month female Maltese (due to health issues with my mother & her inability to care for her).  We recently started "clicker training" for Fred & Bailey (my roommate's dog).  Due to his multitude of "bumps & warts," I am constantly monitoring his skin, but I have recently decreased this & noticed that at least the "attacking" (see below) has decreased.  I have a few concerns that I do not know how to address with Fred.
1.)  He is constantly licking himself (paws, tail, belly...) which has recently decreased (I have tried, Bitter Apple & verbal cuing) recently I have ignored it.

2.)  He attacks (mainly me); this can happen when he is startled or after I have been petting him for a few seconds (when I first got him, it happened primarily when he would be startled, ie if touched when sleeping).  However, it has become more frequent & less consistent the last 4-6 months.  We, moved into a different rental house about the same time (I don't know if there is an association or not).  I did notice the last time I was attacked that he turned his back toward me before I started to pet him.  I petted for 3-4 strokes.  Then, he "went off."  Fortunately, he has no teeth.  What I mean by "attack" is that he will actually try to bite & attack which has left some pretty good bruises, but fortunately has not broken the skin, yet.  He rarely "attacks" my roommate.  I have tried a variety of reprimands for his behavior without much luck.  I have tried "time outs," verbal reprimands, & I have even tried to pick him up & console him (this seems to settle him, but does not decrease the frequency).
He has 4 beds in the house in various places.  Even if he is wide awake with no chance to startle him, he will frequently go into "attack mode" if attempts are made to move him from the bed.  Sometimes he will not even leave the bed for treats.

3.)  He has become very "whiny" lately (more toward my roommate than myself).

4.)  He is very disinterested in me.  He wants to be petted, sat with, picked up, by my roommate, but not so much with me.  In fact, if he is seeking attention from my roommate & I call him to me, he will go to his bed & lie down completely avoiding me.  He was sitting on the couch with my roommate the other day & I sat beside him.  He immediately jumped off the couch & went to his bed.  

5.)  We recently started "clicker training" but Fred seems completely disinterested at times.  He

6.)  He sleeps in bed with me, but recently has decided he likes to get out of bed & go under the bed at night.  this is fine, but he does not like to come out from under the bed in the morning.  If I try to "pull" him out I am afraid I will be attacked.  I used to be able to coax him out from under the bed with a treat & could then pick him up to go out & potty.  He has now figured this trick out & will no longer come out for treats.  I have recently put a blanket under the bed which he will lie on.  Then, I can slide the whole thing, blanket & Fred, in the morning & pick him up to go potty.  It would not be such a big deal, but if he does not go out to potty in the morning, he makes messes in the house.

7.)  I am unsure how to acclimate Fred to my mother's dog when she arrives.  I want him to know that he is still MY dog & I love him, but I will obviously have to give attention to the new dog as well.

We have considered the possiblity of dementia, but I don't think it really fits.  He does NOT wander aimlessly, get lost, go to the wrong side of the door to go out or any of the other things I have been told are signs.
My roommate's dog has recently become more aggressive toward Fred, especially when he approaches my roommate.  So, I don't know how or if this plays into the whole picture.  

I just have concerns for him & feel like I am letting him down.  He had such a bad life before I got to him.  Up until ~ 6-8 months ago, he was somewhat cuddly, would voluntarily sit with me, liked to be petted, & seemed more playful in general.  I am only hoping that I can get that back again.  

Unfortunately, I don't have much health history prior to his rescue.  He has had a DAP collar on for the last 2-3 days & I have been using lavendar oil to help "settle" him as was recommended by my roommate.  I am also going to purchase Hill's Prescription Diet b/d food for him as soon as I can find it (I was told by someone else this might help).

I know this was a very long description, but I appreciate your willingness to help me.
Thank you in advance for your time.  I hope we can help Fred to be a happy, playful dog again!!

Courtney

Answer
First, remove the DAP collar; second, do not go to any diet without recommendation from veterinarian.  He should be seen by a veterinarian who can test him for neurological problems and cognitive dysfunction, both of which he might suffer at his age and would contribute to his negative behavior.  Stop asking your roommate for expert advice regarding behavior modification.  Your problems are far too complex to address in this venue.  You need to locate a credentialed behavior expert (NOT a dog trainer).

It appears that your dog might be suffering from some rank opportunism which is being worsened by your obvious fear of his behavior and the younger male's obtaining higher rank over him in your household.  Before introducing the female pup, you need to have an expert observation, case history, and full veterinary consultation results available to a behaviorist who can then advise both you and your roommate on the best way to proceed.