He should take strict precautions if he needs to go out.

Maintain social distancing and proper hygiene .maintain Govt guidelines

In spleenectomy patients  respiratory bacterial infection progress into serious sepsis...he need to be vaccinated with annual influenza vaccine...which prevents many respiratory infections...except covid.. It is important to know that many covid patients will have superimposed bacterial infections.. so if by chance he gets covid .. he has higher risk of having bacterial sepsis ... In his case prevention is of prime importance... If he develops respiratory infections he need to be started on IV antibiotics earlier than the rest... Hope it makes sense to you...

Corona virus enters the body through nose and mouth only and so just make sure to use the mask all the time and not to touch it for any reason and anyone can go for work and needs to maintain social distancing and not to talk in public