in what way does jim assume a father-like role to huck at the end of the chapter temporarily establishing him as a foil to Pap?

Jim is more worried about Huck's reaction to the dead man than anything else. He shows concern for Huck and wants to protect him. Huck's father NEVER considered his feelings or tried to protect him from anything.

"It's a dead man. Yes, indeedy; naked, too. He's ben shot in de back. I reck'n he's ben dead two er three days. Come in, Huck, but doan' look at his face -- it's too gashly."

I didn't look at him at all. Jim throwed some old rags over him, but he needn't done it; I didn't want to see him."