Scripture says you are to love and care as if it was your own body you take care of. Read Ephesians 5:22 to 32.
The basic need is the medicine that the brain needs to operate right, and to help find the correct dosage. It is so easy to forget to take the medicine on time, you could help with that.
Sometimes it seems the anxiety this condition causes seems overwhelming, so they need all the strength, assurance, and calmness you can bring. Simply quietness before the Lord. Remember this is a medical condition, if the body worked correctly the thoughts and actions would be different.
This is a wonderful opportunity for you to grow and truly mature, as you meet the needs of your spouse.