Regarding kicking the shit outta a 70 year old harasser and thief, why not?
Your advice seems interesting.
Will you lead with a right jab or a left cross? Feign as if tying your shoe and toss some dust in his eyes before swing?
When you put this plan into action in the past how did this turn out for you?
I ask because there is some risk after the curb-stomping. I could relate the boring story of a high school buddy of mine that in his mid-20s responded to the judge's question during open court about how many times he hit a man during a fight with, "Before or after he hit the ground?" but suffice to say was not a response the judge admired and respected.
Certainly, escalating a situation which was previously limited to words is a plan of action and I appreciate the initiative being shown. Make sure it is a good plan which can survive first contact. One possible outcome of escalating to using fists is opening the door to the other party being justified to then react by gutting you like a fish or popping a cap or two into your center mass. Does not matter if are dealing with a thief, unfortunately.
Oh, sometimes executing a plan of action that results in bodily harm does not result in criminal charges being filed by the DA nor even a conviction if post bail then are hauled into court. The smaller the community, the more having connections is useful. My mother was mayor so while I poured out a few beers during my under-age drinking there were never rides in the back of a squad car. Lawyering up with a decent criminal attorney can be a surprisingly stiff hit to the wallet and those pesky meetings can blow a hole in an otherwise productive day in the office or on the lake.
And, there is the pesky civil arena. Anyone can sue anyone for about anything so may need to budget for more lawyer fees and time spent in meetings as are in the moment where the right uppercut connects. Winning!
May be worthwhile to review how your wealth is sheltered in case lose a civil suit. You may be able to keep certain retirement assets and your primary residence no matter the size of the civil judgement though even that limited sheltering of assets varies by state. Plan for the possibility that your vehicles, guns, tools, 400 inch bull elk mounts, high school trophies, etc, being seized then disposed of to collect on a large civil award such as can be awarded if the old guy suffered a debilitating injury so needs 24/7 nursing care or wage replacement due to disability.
But, we all get to put plans into place and dance with the consequences. Assault my child then I am happy to go full John Wayne and then not complain if I live in the gray bar hotel when the dust settles. Not much else I would lead me to roll the dice on my freedom and wealth. Hopefully, I get to keep my man card.