What can we do for a better workers comp settlement

My just was involved in a car accident while on the job for a water utilizes company. His left arm was crushed and he had emergency surgery resulting in 2 played in his arm. This was on 9/ 20 2017. He was under Drs care until last month. His work wouldn't let him return to work with restrictions and was more of less had to retire in December. Workers comp sent a letter 2 weeks ago offering $2,902 with future Dr benefits of needed or 3,402 with no future benefits. Is there something we can do?