Hey aJoeBPD81: I'm so sorry your wife's therapist has been ill. One key thing for pwBPD is for them to learn ways to tame their emotions and find ways to self-soothe. DBT is a type of therapy that is frequently used for people with DBT. There is a lot of material to choose from in the links below.
The first link below leads to a self-help DBT website. The 2nd link, DBT Skills Training, relates to a DBT book, ":)BT Skills Training Workshop and Handouts". It makes some lessons available to the public. It appears as if the lessons could stand alone, without the book. If you explore the website, there is mention of a Facebook group, and perhaps a waiting list. I'd think it might be best to jump in without the Facebook option, but it might be something to consider exploring.
DBT SELF-HELP WEBSITE:www.dbtselfhelp.comDBT SKILLS TRAININGhttps://dbtskillstraining.wordpress.com/Books about BPD's who recovered:The Buddha & The Borderline - Kiera Van Gelder (E-Book and Paperback)
Get Me Out of Here - Rachel Reiland (Used Paperback only)
You might be interested in reading a couple of books yourself.
"Feeling Good", by David D. Burns, MD is reviewed in the Learning Center, Book Section on this website. My therapist recommended
The Happiness Trap by Russ Harris. I found that I could access some online material to assist with participating in some exercises suggested in The Happiness Trap. Perhaps, you and you wife might be able to do something like the mindfulness exercise together.
EXERCISES - FROM BOOK" THE HAPPINESS TRAP"https://www.thehappinesstrap.com/free_resources