We had to upsize to accommodate my MIL and her pal Al Z. Heimer. We sold two houses* for about $1.1M total and paid about $900k for one single-story clown house. Happily, it's 3.5 blocks from DH's work. It's value now is $1.4M+, so when Al Z. is gone, we can downsize again. We will probably have to spend about $1M for a 3+2 fixer, ideally about 1600sf. So, $200k the first time, and maybe $500k next time?
*Each house was two-story, with no downstairs bedroom. Boo.