...is he/she still fully entitled to 2nd Amendment rights? In other words, obtain a CHL, possess firearms, etc.?
Yes..., BIMHO, not for much longer.
If the legislation can pass a standard definition on mental disease,
my prediction is that it will be broad enough to cover PTSD, and seek to deny ownership/possession.
As noted above, a slippery slope, but I think we are already on it.