I'm sorry to hear about your arborvitae. Typically when you see browning of arborvitae like in the pictures you attached, there is either too much or too little water. Arborvitae requires moist soil, but too much water can cause root rot, which kills root tissue, impairs water and nutrient transportation, and subsequently causes leaf browning. Check the soil around the tree to see if there is poor drainage. There has also been a lot of drought damage to trees in our region from the past few hot, dry summers. Sometimes drought damage is not visible until the following spring, so you may be seeing damage from last year's drought. You can prevent this kind of damage by watering your arborvitae with a soaker hose about once a week during the summer, but make sure not let the tree sit in a pool of water. 

There is also a chance that an insect pest in responsible for the leaf browning. You might check to see if you see any signs of insects (e.g. frass (saw dust-like insect excrement), eggs, holes in the trunk or branches, tunnels on leaves, webs, small scurrying mites that look like black dots, sticky sap, etc.). 

If you would like to have someone come out to inspect your tree, you might consider contacting a certified arborist. For a list of certified arborists in your area, check out the International Society of Arboriculture website. 

Please let me know if you have any additional questions.