Question ARS and Previous dengue treatment for a Friend

[Naveenkumar2310]

Hi This question is for my friend who is not is there in this forum. My friend suffered a bad dengue fever in Dec 25th 2017 and was discharged from hospital on 31st December. He was treated with lot of IV fluids and some injections and tablets. His plate let count was 100000 on the lower side and then started increasing after one week. It's been 4 months since he was diagnosed with dengue fever. He recently had an exposure 5 weeks back where he involved in one time unprotected sex with a CSW. After 2 weeks he had a little discomfort in his throat (not painful, able to eat and drink water but feeling discomfort in throat), No fever, No rash till date. No Diarrhea but on and off stomach pain, He has lost around 2kgs. main concerns is that he had on and off body pain and tiredness, headache and pain behind the eyes but not something which made him bed ridden. It's been around 5 weeks since his exposure and he will be testing in another one week.

He would like to know,
1. Did he experience ARS symptoms? are his symptoms consistent with ARS or without fever these are not ARS symptoms?
2. Since he was treated with dengue 4 months back which is a typical virus infection, has his treatment with dengue is still active and made this ARS mild?
3. No dengue vaccines were taken but it was injections and fluids and tablets were used. Will that have any impact on the severity of ARS?  
4. He has read some where that previous dengue infection could reduce or mask the ARS? Is it true?
5. Can the treatment taken for previous viral illness is still strong enough to make the ARS mild or It has nothing do with the HIV?

He read some where that dengue antibodies can protect against other dengue viruses and make him immune for another 6 months. So is that the case for any viral illness including HIV or applicable only to Dengue. has the treatment for dengue reduced the ARS to mild symptoms?