We all agree mobile him park owners have a right to income on their investment. Mobile home buyers also have a right to enjoyment of their investment, living in their own home.
In parks for seniors 55+ most of the residents live on fixed incomes, particularly those over 90. It isn't unusual for those closing in on the century mark to have outlived their savings and have social security $700 or less a month. If their space rent goes up to $500 a month or more, you see the problem there.
Additionally, elder mobile home owners may have occupied their home for 30 or 40 years with modest rent increases of 1% a year or less in keeping with the 1968 act providing for senior mobile home parks. This was changed in 1998 allowing mobile home park owners to raise rents with a 90 day notice.
An example would be the mobile home park where I live where rents were seldom increased until 2012 when a new manager took over. Since then rents on my space have been raised $100 a month in two $50 increases.
For the seniors living here 30 years it will be hard for them to move. Their choices are limited to paying, moving, having the coach moved out.
WHAT TO DO
Check your state laws regarding tenant law. There is a national law pamphlet, "Mobile Home Residency Law" for each year. There may be help there. Also check for City Ordinances regarding rents. A list of California cities with mobile home rent restrictions is here. They have saved some people. In Calistoga California and other places City Ordinances have protected mobile home owners from ruinous rent increases.
If you have received notices of unfair rent increases a good place to start is The Fair Housing Council in your area.
Good luck to you.