Services terminated without Employment Letter

My father was transferred from parent company to a group company in the logistics sector. He only received the transfer letter and was assured of all benefits including stock options as mentioned by the parent company. Although the transfer letter mentioned enclosure of new Employment Letter to be issued by Logistics company but was never issued. After few years the Logistics company terminated the services of my father without giving the stock options. 1. Is it legal for Logistics company to not to issue employment letter? 2. If there is no appointment letter issued by Logistics company, is it legal for them to terminate services? 3. What could be the penalty for such act by Logistics company? 4. Parent company never terminated his services, till date. What can we claim to them? 5. Stock options were part of compensation as mentioned in the transfer letter too. My father received stock options in 2005, 6 and 7 but later there were delays. Can we claim this stock option now? My father crossed 60 in 2016. What damages and claims can be made? Regards