Gold Card: Please help

I am applying for my dad to get the Gold Card in Texas. He just had a stroke in February so he can’t work until he recovers. He needs therapy and a surgery to do so.

Before he gets approved, he needs someone to fill out a form named “Statement of Support” which claims that this person has been paying for his bills whiles been out of work. I don’t live with my dad, neither does my mom as my parents are divorced. His brothers have been giving him money here and there to help because they owe him money so ideally they would fill out the form for him.

The problem is that the bottom of the form says “I understand that I am not responsible for his medical bills unless I have a legal responsibility to support him.” Because of this verbiage my sister and I are scared to sign it and my uncles won’t do it.

Does anyone know how someone would become financially responsible for him? I’m 30 with mortgage and a business so I’m terrified of taking on the debt.