Didn’t pay a final installment of $15k & now owe $150,000 (CA)

My partner, luckily not married, was paying off an attorney who he spent over $500k with. The attorney didn’t send him the payment link for the final payment & even though he requested it twice, he didn’t pay through any alternative method. He didn’t pay at all. He also just missed his court date & supposedly owes $150k in attorney fees. Now what? There is a lien on our home & a process server is on his trail. Is that $150k automatically set in stone, or can this Delbert resolve this another way? We share a child, his elderly mom is being bothered by ppl at her door, & so I’m motivated to help resolve this. Thank you.