This is not necessarily the end of the world.
No, you cant remove him from the policy if he is a true owner.
Some policies have a "Primary Owner" & a "Contingent owner"
Others have a "Primary" owner and an option of "Secondary" owner or "Co-owner".
If it is either of these two cases, and if he is not the "primary"; the Primary Owner may remove him from the policy.
If he is a true 50/50 owner of the policy, and both sons have to both physically sign off on any changes, then only he may remove himself.
But the other son may make payments on the other owner/payors behalf.
So can you most likely.
Also, if the policy lapses due to non-payment; you could try contacting the Company and see if they will let you take over as Owner; once a policy is lapsed, some companies give the Insured this option.