Investing on Behalf of or Maybe Commingled with Parents

[Daniel L.]

My parents have equity in a property of which drawing $200k on the HELOC in no way risks their livelihood. They've done so before for investment purposes and wish to exercise it again. They're wanting to explore one of two things.

1. Having me invest the funds with my wholesaling regime or
2. Having me partner with a local builder with an A+ track record for transparency/integrity/investment acumen (hundreds of deals)

They'd like me to exercise the investment decisions and just give them periodic status updates and not have to double signature anything. What custodian options are available to us other than my getting power of attorney? Is there such a thing as power of attorney over only one HELOC or savings account? (We currently have shared checking & savings accounts) Lastly, I'd like to know what tax implications might result if the HELOC funds were just transferred into our joint savings or checking and then ultimately leveraged for wholesale purchases or put into escrow for use in partnering with the builder. Any and all insight is greatly appreciated!