it think it might depend on what your older son and his friends are into?
I can recommend the Hotel Tannit in San antonio whichis about a mile out fromthe centre, its a family style hotel and offers half board or all inclusive. Its far enough away from san antonio town to avoid the noise etc but its still close enough for your son and his mate to go into on a night.
there are a number of posts on this forum on this hotel, this should give you a flavour for what its like.
if your older son and his mate arnt into city centre type nights out then you could consider something a little more reserved such as ibiza town or possibly Santa eulalia