Welcome to the forum!!!
I would strongly suggest that your ex-husband sees a llmd (Lyme literate MD) as soon as possible. He had the tick bite, and was not sufficiently treated (4 weeks of Doxy that weren't finished, or even hardly started).
If you want us to help you find a llmd, you can start a new thread 'Looking for LLMD in______'. You will have to enable your email address though (My Profile, Edit Profile, show my Emailaddress), cause we are not allowed to put dr's names on the forum.
Depression and mental unstability are definitely symptoms of Lyme Disease (and also Bartonella, a so-called LD coinfection).
You can have a look at this article:
Insomnia is a very irritating symptom we deal with, I was forced to go on Klonazepam to get about 7 hrs of sleep a night, without it, I get 2 hours. Some nights it doesn't even help, I often need to add antihistamine to get my heartrate down.
about the tendonitis: please tell his mother that steroids are very very bad for him: steroids suppress the immune system, and since we already have a compromised immune system, it can make things much much worse!!
I don't know if you have been going through the top thread on the Lyme page 'New to Lyme?.... Start here!'? It is packed with useful information that will certainly answer some of your questions: symptom lists of LD and coinfections, different treatment options, detoxing methods, usefull links, etc.
Don't hesitate to post if you have any more questions!