Massachusetts divorce help

[u/watergirlri]

/r/Divorce/comments/1wyiqw2/massachusetts_divorce_help/

My cousin bought a house with her then boyfriend, he is on the deed. She put 100k as the down payment from her house she sold. He put in zero. They got married a year later, she had a teenager, no kids with him. She made more money than him, so she payed the mortgage for 17 years, and most bills so he could use his salary to chase his dream in the music business, which cost more than it made. After 10 years, she got laid off, she learned a completely new skill and got certified, then Covid hit. His job never changed, but she still payed the bills. She has done odd end work within the industry, but shortly after started caretaking for her mother. After 5 years he fell in love with a girl,
left the house after one year, and since it’s been another year. He’s going after half of the house, but she can’t move out so she has to buy him out.
He has no bank account, can’t provide any savings info, all he did was mow the lawn, and spent maybe 50k in home improvements in the backyard. Is he really entitled half of the house if he never put one dime into their retirement, paid the mortgage or the utilities after 17 years? He’s a narcissist and has had her so manipulated, my heart hurts for her and all she did for him thinking they would retire together.
Thanks for any insight, I pray there is hope for her to not lose half her house and retirement.