Late diagnosis

Are there any parents out there who have an adult child who has been diagnosed with autism late in life (ie after they left school?) Out 25 year old son is currently undergoing an autism assessment and the signs are that he is likely to get a diagnosis , which is likely to come as a shock to him. Some support / advice/ tips on how to support him would be very helpful as so many resources are aimed at school aged children. Thankyou.