But at the same time, by the time we find the second property, APR on the HELOC may be way higher and my credit will be impacted by the large unused credit line.Any thoughts?

@Marcus Auerbach quite an interesting impact this pandemic has had.

What are some articles on BP that have impacted you & your investing career the most?

that may impact what you do.

If they stop paying rent and lose the mobile home, that should have no impact on your mom.

Building Coverage – this mitigates and restores the building from covered losses and this coverage is required by lenders to secure loans.Building Coverage – i.e. fire, wind, water, vehicle impacts and other elements of structural damage.Loss of Rents/ Business Income Coverage – pays for loss of rental income when a building that is rented to others is damaged by a covered loss.

I would be less concerned with one person owning these rentals and more concerned with the fact that 90% of the other properties in the neighborhood are in fact rentals, since this could impact a few things for you.You'll see what I mean in condo associations for example. 

I read Taylor's reply and want to add some additional thoughts ... are any of the tenants currently behind in their rent and/or known to be employment impacted by the virus?

Huge impact on family life, sleep, etc...

HelloI am not a building science expert but I sparingly use my air-conditioner during summer on most occasions a fan best works for me.But since fan doesn't get rid of the humidity from air inside home,would it impact the durability of the building inside or negatively impact in any other way?