Oh, sweetheart, I am so sorry, you are having such a rough time, especially after you have been so brave in returning home....first I wanted to say what a wonderful, thoughtful Vet you have in sending you a card with Cooper's paw print in,...a real memento for you to treasure, I know It must be heart rendering to look at at the moment, but you'll be so glad that you have such a personal keepsake.
My heart is going out to you to have to see Arley suffering a seizure, you must have been petrified...I know how frightening they are, Millie also has a heart condition, and sometimes she has these too...quite recently she had two in as many days, and her cardioligist couldn't be sure if she had had a simple faint, siezure, or a heart attack....course at the time my stomach was in knots, terrified that this was going to be 'the time' that my vet and her cardioligist had warned me could happen since Millie was a baby,...she has defied all odds, and is six years old this year!!....Poppy also suffered multiple siezures ( because of her brain tumour), and the symptoms you describe do sound like a common siezure.....but I do agree with sidhewlf it would put your mind at rest to have the bloodwork done, so you can get a better insight on the problem,....on the other hand it may also be true that Arley has been so stressed with losing Cooper, picking up on everyone else's distress, going back home, disruption in almost everything really, that has stressed him enough to bring this on, and it could turn out to be an isolated episode that will never reoccur....I am praying that this is the case and that Arley will stop giving mummy such a fright!!!...... I am sure that your bad times are over now, and that things will gradually calm down, and return to normal...I've said before, all the positive energy and love you find here from everyone on BW can work miracles, and you sweetie, deserve every last bit of love, healing vibes, and positive thought power that all of us here can muster. You have been through enough to break anyone lately..but I know how strong you are....so keep on thinking positive thoughts, and carry on being as brave as you are...good luck,...I will keep you in my thoughts (((((((( HUGS ))))))))