is of course the option 1 they will use if there are no values to collect - and that will be over his head for ever, but agree - there is not so much more to do than to try and get a new payment agreement, or to continue as best one can.
It is tough to have debt to tax (and I suppose rightly so as we would probably otherwise always avoid paying tax as indendent persons) as they can indeed hold back salary through employers or - for businesses demand prepayment/security for VAT and for tax + at worst - they can get declaration for personal bankruptsy (will do that simply if they cannot claim the money through values or withholding salary) = goodby to bankconnections and lots of trouble for the company run as personal company
Do you think it is possible for me to take over some part of his debt ? Would it make any difference?
no that would not be possible but you could give him af gift - with tax on that gift after gift tax rules) which would not make much sense. If they might accept that you bailed for the amount is hard to say but could be offered - so IF he did not pay in full within - now new 12 month - you would have to pay?
The easier option, if you have the money, is that you lend him the money - on a one year lend - he pays tax NOW and then you instead of tax over a year - no tax consequence but clearly your risk.
Almost all of the above would make sense, except for bankruptcy and closing the company, because the only good source of income will disappear
that should be considered also by the court in case of claim for bankruptcy - they will look into consequences of losing job - income possibilities and all -