Could a US citizen with a UK Long Term Family visa alternate 90 day periods in the UK and Switzerland indefinitely? Switzerland is a Schengen country, but the UK isn't.
Background: my mother in law is ready to retire. We live in Switzerland, her other daughter is in the UK. Our thought: she could spend 90 days here, 90 to 180 in the UK, then 90 here, or even alternate months.
Related: is there a Swiss equivalent to the Long Term Family visa that would simplify the process?