Maybe they should go the Allan Quartermain route... Allan Quartermain could be Indiana Jones' real dad and for sake of protecting his family he changed his surname to 'Jones' and moved to Utah... I mean, Connery WAS Quartermain (in probably the worst connery role ever).. That's NEW canon. Then Disney could be blamed for hijacking.err...buying another IP out and being even more unoriginal.
Picture it, 1971, old man Indy has been diagnosed with cancer (probably from multiple radiation exposure over the years; ark, aliens.err. inter dimensional beings, nuke blast, etc). He's pretty much given up and accepted his fate, but out of nowhere, his other unknown b@st@rd child (plot twist, Willie's kid!), has tracked him down to his adhoc studio apartment above a pharmacy outside of Seattle and tells his about him and his moms' past. Apparently, before his mom died in a freak circus act involving her being attacked by a rabid mouse who spooked the elephant she was riding around the big top, who then threw her off and stomped on her back, she finally revealed who his father was. Surprisingly enough, the elephant only paralyzed her from the neck down, but the peanut butter and jelly sandwich that she was given in the hospital during her recovery did her in. Turned out that Willie had a severe peanut allergy. Her dying words to her son (Chip's his name BTW), "Indiana..... Jones.... is... your.. f#C!in' father..." After Indy chuckled to himself and exclaimed 'Willie Willie Willie', he then remembered that the guy telling him the story was her son and that he should feel some sorrow...
Indy then goes on to tell Chip that he now belongs in a museum, and asks if he could borrow some money to buy some drugs. Chip, devastated to see that his once great rogue of a dad has resigned himself the remaining life he has living in a drug induced state of haze, decides that he'd can't see him 'going out that way', and the old man's got one final adventure in him. You see, Chip has been the director of antiquities for Southern Southwestern Louisiana Community College (you could say he's a "chip" off the old block!) for the last 12 years and has come to know the conclusion that voodoo is indeed, real. Determined to not let his dad die, he's heard rumors of a 147 year old witch doctor who has kept people alive thru some ancient Haitian incantation involving eating pieces of flesh from an ancient shrunken head and reciting klaatu barada nikto! 3 times while moonwalking. Indy's reluctant at first, but realizes that even if Chip is full of crap that he could probably score some major hallucinogenic hooch to relieve his daily life of constant pain.. 'What the he!!', Indy mutters...
Let the adventure begin.