For the record, what your old manager was doing (directly asking you about your mental health status in a quasi-interview setting) was probably illegal, at least in the US (IANAL). There are pretty strict rules around the kinds of things that employers are allowed to ask prospective employees about, and health (mental or otherwise) is very much on the "not allowed" list.
Employees have a legal right to protection from discrimination along those lines, and companies (no matter how small) most definitely do _not_ have the right to discriminate in that way.