I'm sure there will be lawsuits, because that's what people do these days -- sue. Whether the lawsuits will get any traction is a different matter. I'm sure OceanGate is a corporation, so it could be interesting to see if the lawyers try to "pierce the corporate veil" and go after Rush's personal estate, or some of the other OceanGate employees and suppliers.
They'll have an uphill climb. It has already come out that multiple sources with expertise in submersible design and construction told Rush that his design was dangerous, and he dismissed their concerns as being unfounded. Any defense will probably start with the guy Rush fired in 2018 for having the audacity to suggest that they should have the hull tested.
Just found an article in which the guy who was scheduled to go on this dive -- with his son -- and who backed out says that Rush told him the trip was safer than crossing the street. As I said early on, it ultimately comes down to hubris. Rush obviously believed his toy was safe, but his fervent belief basically made him blind to reality.
https://www.the-sun.com/news/8440488/oceangate-stockton-rush-titan-sub-safe-half-price-tickets/