Depression is part of MS, some have anxiety too. Depending on where the lesions in the brain are, some of us have challenges with filtering out thoughts and frustrations, reasoning, calculations, feelings. All can also be out of synch because of some of the medications we take too that can make matters worse. Those of us with MS need to report these symptoms to our MS Specialist Neurologist so that these symptoms can be managed by adjustments in medications we take. This is usually very hard for us to admit, and by the time we do we have probably burnt a few bridges of relationships with friends and family and co-workers. I would encourage you to ask him if he realizes that it is happening and that it is not his fault, that perhaps he should let his MS Neurologist know so they can help him with these changes happening with his MS.
Do you know how long he has been diagnosed with MS and if he is taking any (which one) of the MS Medications (we call them DMD for Disease Modifying Drugs). Some of those medications have known side effects for some psychological and personality changes.
Please check out the National MS Society Website and look under "Care givers" and you should be able to find some good articles on many things in living with or helping someone who has MS.
Good Luck & Blessings,
RRMS diagnosed 2006
Tecfidera Started April 2013