LTD insurance monthly payments received. no w-2 or 1099 provided by either the former employer or insurance company. who is responsible to provide tax form?

my husband received long term disability insurance monthly payments in 2017 which continued after his employer terminated him for being on disability for one year. both the insurance company and his former employer state that they do not provide a 1099 for the payments. federal income tax was withheld. who is responsible for provide documentation? how do i obtain the appropriate form?