In need of advice

So my best friend has a 3 year old little boy he is so hyperactive he wakes up and is bouncing off the walls she’s been told he has adhd but can’t be fully diagnosed yet as his to young and putting him to bed is impossible she tried every night at about 8pm and his constantly jumping around still at about 4pm his now in nursery she was hoping he would get tired out durin the day but out of no where he seems to have more energy she tries not to give him any sugar but the occasional sweet or chocolate etc I’ve been at hers for a couple of knights and managed to get him to sleep but he sleeps for no longer than an hour and then is just bouncing off the walls again the doctors wanted her to put him on medication and she tried everything else first then eventually tried the medication but it seems to make him more energetic had anyone else had this problem only no how I can help her she’s barely sleeping and this has been going on since he was born so it’s really not good for either of them any advice would be great thank you in advance