Whilst that's a perfectly valid hypothesis, they explicitly did test for relationships with rises in opioid misuse and didn't find evidence to support it. There isn't even consistent empirical data to show unemployment as a causal factor in aggregate increased drinking, never mind it being concentrated among recently laid off early onset dementia patients. The reality is unemployment influences some people to drink more and others to drink less, the circumstances of the unemployment and the demographics of the individual matter as do the patterns of the drinking, and even the statistical relationship between drinking and dementia is complex as statistically the lowest risk behaviour tends to be "moderate" rather than zero alcohol consumption